Welcome!
It seems like a hard drive problem is the most likely. I suggest that you test your Seagate drive first with SeaTools:
| Seagate
Test your WD drive next:
WD Support > Downloads > SATA & SAS > WD Caviar Black Code:
ERROR_CODE: (NTSTATUS) 0xc000000e - A device which does not exist was specified.
DISK_HARDWARE_ERROR: There was error with disk hardware
Other than that, all I can suggest is removing some more risky drivers/programs.
Remove Avast with this tool:
http://files.avast.com/files/eng/aswclear5.exe
Replace it with MSE:
http://www.microsoft.com/security_essentials
Also remove Comodo, and just use the Windows Firewall instead.
...Summary of the dumps Code:
Built by: 7600.16617.x86fre.win7_gdr.100618-1621
Debug session time: Wed Nov 24 12:34:57.346 2010 (UTC - 5:00)
System Uptime: 0 days 4:42:10.190
BUGCHECK_STR: 0x7a_c000000e
DEFAULT_BUCKET_ID: CODE_CORRUPTION
PROCESS_NAME: System
FAILURE_BUCKET_ID: MEMORY_CORRUPTION_LARGE_4096
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