I was having a similar problem, not quite as severe though.
My System process was running at a steady 16% no idea why this started although I had just managed to get a virus the day before.
Anyway I had cleaned my PC and removed all traces of everything and I noticed this was running at 16%
I have Remotely Anywhere installed on my PC which has many options for managaing a PC not just screen takeovers.
The process viewer on this showed me some quite interesing results (See Below) this led me to think it might be a hardware thing.
First thing I did was unplug a USB multiformat card reader and Hub, which also had a USB Plantronics headset in it.
Seconds after doing that it dropped back to 0%

not sure yet if it was the card reader or the Audio componets of the Headset (As it has it's own sound card built in)
So if I were you guy's I would slowly start stripping bits of hardware out till you find a culprit.
P.S. I am an MCSE and that wasn't easy let me tell you I have an entire forests worth of manuals that ocompanied quite in intense set of courses.
It was well worth it in the end though.
P.P.S
Let me know how it goes.
P.P.P.S
You don't have to qoute an entire post and then reqoute and qoute it again, all it does is fill the screen up and makes me want to stop reading it.
Info From Remotely Anywhere on the "SYSTEM" Process
Threads
ID Creation Time Base Priority Priority State Wait Reason Processor Time Kernel Time User Time User
8 0 0 Waiting Free Page 04'766 04'766 NT AUTHORITY\SYSTEM
16 2006-01-12 22:41:03'50 13 13 Waiting Event Pair Low NT AUTHORITY\SYSTEM
20 2006-01-12 22:41:03'50 13 13 Waiting Event Pair Low 02'022 02'022 NT AUTHORITY\SYSTEM
24 2006-01-12 22:41:03'50 13 13 Waiting Event Pair Low 06'489 06'489 NT AUTHORITY\SYSTEM
28 2006-01-12 22:41:03'50 13 13 Waiting Event Pair Low 05'277 05'277 NT AUTHORITY\SYSTEM
32 2006-01-12 22:41:03'50 13 13 Waiting Event Pair Low 07'040 07'040 NT AUTHORITY\SYSTEM
36 2006-01-12 22:41:03'50 12 12 Waiting Event Pair Low NT AUTHORITY\SYSTEM
40 2006-01-12 22:41:03'50 12 12 Waiting Event Pair Low NT AUTHORITY\SYSTEM
44 2006-01-12 22:41:03'50 12 12 Waiting Event Pair Low '020 '020 NT AUTHORITY\SYSTEM
48 2006-01-12 22:41:03'50 12 12 Waiting Event Pair Low '010 '010 NT AUTHORITY\SYSTEM
52 2006-01-12 22:41:03'50 12 12 Waiting Event Pair Low '781 '781 NT AUTHORITY\SYSTEM
56 2006-01-12 22:41:03'50 12 12 Waiting Event Pair Low 01'381 01'381 NT AUTHORITY\SYSTEM
60 2006-01-12 22:41:03'50 12 12 Waiting Event Pair Low '510 '510 NT AUTHORITY\SYSTEM
64 2006-01-12 22:41:03'50 15 15 Waiting Event Pair Low NT AUTHORITY\SYSTEM
68 2006-01-12 22:41:03'50 14 14 Waiting Executive NT AUTHORITY\SYSTEM
72 2006-01-12 22:41:03'52 8 18 Waiting Virtual Memory 01'802 01'802 NT AUTHORITY\SYSTEM
76 2006-01-12 22:41:03'52 8 17 Waiting Free Page NT AUTHORITY\SYSTEM
80 2006-01-12 22:41:03'52 8 16 Waiting Executive '010 '010 NT AUTHORITY\SYSTEM
84 2006-01-12 22:41:03'52 8 23 Waiting Executive '070 '070 NT AUTHORITY\SYSTEM
88 2006-01-12 22:41:03'57 8 16 Waiting Event Pair Low NT AUTHORITY\SYSTEM
92 2006-01-12 22:41:03'57 8 17 Waiting Event Pair Low NT AUTHORITY\SYSTEM
96 2006-01-12 22:41:03'72 8 8 Waiting Executive '020 '020 NT AUTHORITY\SYSTEM
100 2006-01-12 22:41:03'73 8 17 Waiting Virtual Memory NT AUTHORITY\SYSTEM
104 2006-01-12 22:41:03'96 8 16 Waiting Executive NT AUTHORITY\SYSTEM
108 2006-01-12 22:41:03'96 8 16 Waiting Executive NT AUTHORITY\SYSTEM
112 2006-01-12 22:41:03'96 8 16 Waiting Executive NT AUTHORITY\SYSTEM
116 2006-01-12 22:41:03'96 8 16 Waiting Executive NT AUTHORITY\SYSTEM
120 2006-01-12 22:41:08'15 8 8 Waiting Event Pair Low '010 '010 NT AUTHORITY\SYSTEM
128 2006-01-12 22:41:09'98 8 8 Waiting Executive NT AUTHORITY\SYSTEM
132 2006-01-12 22:41:09'98 8 8 Waiting Executive NT AUTHORITY\SYSTEM
136 2006-01-12 22:41:09'98 8 8 Waiting Executive NT AUTHORITY\SYSTEM
140 2006-01-12 22:41:09'98 8 8 Waiting Executive NT AUTHORITY\SYSTEM
144 2006-01-12 22:41:10'10 8 9 Waiting Executive NT AUTHORITY\SYSTEM
148 2006-01-12 22:41:10'20 8 16 Waiting Executive NT AUTHORITY\SYSTEM
152 2006-01-12 22:41:10'22 8 16 Waiting Executive NT AUTHORITY\SYSTEM
172 2006-01-12 22:41:11'93 8 8 Waiting Executive NT AUTHORITY\SYSTEM
176 2006-01-12 22:41:11'93 8 8 Waiting Executive NT AUTHORITY\SYSTEM
280 2006-01-12 22:41:11'95 8 9 Waiting Suspended '610 '610 NT AUTHORITY\SYSTEM
348 2006-01-12 22:41:12'09 8 31 Waiting Executive NT AUTHORITY\SYSTEM
352 2006-01-12 22:41:12'09 8 9 Ready 11'035 11'035 NT AUTHORITY\SYSTEM
356 2006-01-12 22:41:12'17 8 9 Waiting Suspended NT AUTHORITY\SYSTEM
360 2006-01-12 22:41:12'25 8 9 Waiting Suspended NT AUTHORITY\SYSTEM
364 2006-01-12 22:41:12'33 8 9 Ready 09:09'219 09:09'219 NT AUTHORITY\SYSTEM
372 2006-01-12 22:41:13'29 8 8 Waiting Executive NT AUTHORITY\SYSTEM
552 2006-01-12 22:41:13'96 8 8 Waiting Event Pair Low NT AUTHORITY\SYSTEM
560 2006-01-12 22:41:13'96 8 8 Waiting Event Pair Low NT AUTHORITY\SYSTEM
564 2006-01-12 22:41:13'96 8 8 Waiting Executive NT AUTHORITY\SYSTEM
568 2006-01-12 22:41:14'01 8 24 Waiting User Request NT AUTHORITY\SYSTEM
588 2006-01-12 22:41:22'72 8 9 Waiting LPC Receive NT AUTHORITY\SYSTEM
1800 2006-01-12 22:41:46'83 9 9 Waiting Event Pair Low NT AUTHORITY\SYSTEM
1804 2006-01-12 22:41:46'85 9 9 Waiting Event Pair Low NT AUTHORITY\SYSTEM
2292 2006-01-13 00:46:32'90 8 8 Waiting Event Pair Low NT AUTHORITY\SYSTEM
Registry Keys In Use
HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter
HKEY_LOCAL_MACHINE\HARDWARE\DESCRIPTION\System\MultifunctionAdapter
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 2
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 2\Scsi Bus 0
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 2\Scsi Bus 0\Initiator Id 15
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 3
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 3\Scsi Bus 0
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 3\Scsi Bus 0\Initiator Id 255
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 3\Scsi Bus 0\Target Id 0
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 3\Scsi Bus 0\Target Id 0\Logical Unit Id 0
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 3\Scsi Bus 0\Target Id 2
HKEY_LOCAL_MACHINE\HARDWARE\DEVICEMAP\Scsi\Scsi Port 3\Scsi Bus 0\Target Id 2\Logical Unit Id 0
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\Class\{36FC9E60-C465-11CF-8056-444553540000}\0000
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\Class\{36FC9E60-C465-11CF-8056-444553540000}\0001
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\Class\{36FC9E60-C465-11CF-8056-444553540000}\0002
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\Class\{36FC9E60-C465-11CF-8056-444553540000}\0003
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\Class\{36FC9E60-C465-11CF-8056-444553540000}\0004
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\Class\{36FC9E60-C465-11CF-8056-444553540000}\0004
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\ProductOptions
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\Session Manager\Memory Management\PrefetchParameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Control\Video\{6CD44DFF-A0DA-41F9-9BB6-9D7175785AAF}\0000\VolatileSettings
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\PCI\VEN_1106&DEV_3038&SUBSYS_80ED1043&REV_81\3&267a616a&0&80\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\PCI\VEN_1106&DEV_3038&SUBSYS_80ED1043&REV_81\3&267a616a&0&81\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\PCI\VEN_1106&DEV_3038&SUBSYS_80ED1043&REV_81\3&267a616a&0&82\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\PCI\VEN_1106&DEV_3038&SUBSYS_80ED1043&REV_81\3&267a616a&0&82\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\PCI\VEN_1106&DEV_3038&SUBSYS_80ED1043&REV_81\3&267a616a&0&83\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\PCI\VEN_1106&DEV_3104&SUBSYS_80ED1043&REV_86\3&267a616a&0&84\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\PCI\VEN_1106&DEV_3104&SUBSYS_80ED1043&REV_86\3&267a616a&0&84\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\PCI\VEN_1106&DEV_3104&SUBSYS_80ED1043&REV_86\3&267a616a&0&84\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\Root\PORTS\0000\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\Root\PORTS\0001\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\USB\ROOT_HUB20\4&2556a5a7&0\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\USB\ROOT_HUB\4&1a8f66bb&0\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\USB\ROOT_HUB\4&2d491760&0\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\USB\ROOT_HUB\4&467fdfe&0\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Enum\USB\ROOT_HUB\4&7d5b616&0\Device Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\ACPI\Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\Avg7RsXP\Parameters
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\Eventlog
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\LMIInfo
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\LMImirr\Device0\VolatileSettings
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\RAInfo
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet003\Services\ramirr\Device0\VolatileSettings
HKEY_LOCAL_MACHINE\SYSTEM\Setup
HKEY_LOCAL_MACHINE\SYSTEM\WPA\ExHashAlgID-XT33R8KXVF2JY7
HKEY_LOCAL_MACHINE\SYSTEM\WPA\HashAlgID-XT33R8KXVF2JY7
HKEY_LOCAL_MACHINE\SYSTEM\WPA\HashID-HWYK8KK3W2P24B
HKEY_LOCAL_MACHINE\SYSTEM\WPA\HashID-XT33R8KXVF2JY7
HKEY_LOCAL_MACHINE\SYSTEM\WPA\Key-QQDRV3JCYR96TMX49FWYR
HKEY_LOCAL_MACHINE\SYSTEM\WPA\Key-XX3FW2QKHRDQCR7PBJYDG
HKEY_LOCAL_MACHINE\SYSTEM\WPA\PnP
HKEY_LOCAL_MACHINE\SYSTEM\WPA\ReHashID-XT33R8KXVF2JY7
HKEY_LOCAL_MACHINE\SYSTEM\WPA\SigningHash-HWYK8KK3W2P24B
HKEY_LOCAL_MACHINE\SYSTEM\WPA\SigningHash-QCCYKBJBDYRHTP
HKEY_LOCAL_MACHINE\SYSTEM\WPA\SigningHash-XT33R8KXVF2JY7
>> Stay informed about: ""system"" process staying over 80% of cpu