I have been getting many different stop codes for all of these crashes, and only can recall two at the moment. 'IQRL_NOT_LESS_OR_EQUAL' seems to be a common one, and others have been caused by win32k.sys or usbstor.sys.
Attached are my dump files.
Windows 7 Professional x64
Fresh install about a year ago
Full retail (not sure, was free through student MSDN account)
Hardware: All original back to July 2007, except PSU and GPU (about 2 years old)
RAM was also upgraded a few years back.
The system is getting older, and I am planning on building a new one once I start my new job, but for now I would like to get this one working again. I am going to run MemTest next...
Thanks for the help!