Question : Problem: Computer freeze/lag .. wierd!

I'm a bit confused - my computer has always run very well and I haven't made any hardware or software changes. All of the sudden my computer is spiking, and I can't see any one program or device that's causing it. I tried unplugging everything but the essentials but i'm still randomly getting spiked. Moreover, I recently reformatted and removed the bare devices (usb) and installed the bare drivers needed and it still happens! The standard trouble shooting steps I have tried: remove as many devices as possible, minimal install, safeboot, etc. I'm wondering if there's a tool I can use to check all hardware beyond chkdisk and the like. I'm hoping for a free/GPL solution if possible. The freeze usually lasts for 2-3 minutes then resumes. Other times it just chops up my experience in an application to weird random slowness :S

Any input/help greatly appreciated - thanks.

SYSTEM
Windows Vista 64-bit
Single Geforce 8800 Ultra [not OC]
680i nvidia sli mb
Pentium q6600 (quads not OC)
4 gig nvidia sli ram OCZ

(can provide more specs if necessary)

Answer : Problem: Computer freeze/lag .. wierd!

There's the UBCD http://www.ultimatebootcd.com/ and the UBCD4Win (needs work to make the disk but instructions are on site) http://www.ubcd4win.com/

You could always try a Knoppix disk http://www.knoppix.org/  If it runs OK in Knoppix without freezing up then it's a Vista problem.

Oh, check fan on CPU.  You're not getting too hot and the CPU is throttling back to control heat?  Look at Speedfan http://www.almico.com/speedfan.php to monitor your temperatures.