HELP! Severe stuttering, lockups & DPC latency issues

Hi, for the last little while I've been having some severe problem that is making my PC basically unusable for the most part. Basically I will get sever hiccups and lags on my system that will last for about 30-40 seconds and this will happen practically every 1-2 minutes. It's not a video or audio issues as it effects the whole system regardless of what I'm doing (ie simple browsing or intense gaming = same issue).

So I loaded up the DPC Latency checker and this is what I get.


This is the normal latency values I get for maybe 1 or 2 minutes..
http://img37.imageshack.us/img37/7746/44777117.jpg

THEN
http://img697.imageshack.us/img697/7890/51189666.jpg

As you can see there is this severe and very regularly spaced latenc issue and my stuttering coincide perfectly with these spikes. This constant spiking every 3 second will continue for 30-40 seconds. Then it will go back to the previous graph.

What's interesting is that this happens right away after I start my computer and that these spikes occur pretty much regularly with only a minute gap of normal performance and will cycle back and forth between these phases forever.

I have used the device manager to disable my video card and audio cards and some other devices to pinpoint the problem to no avail. The spikes still continue to occur.

This is seriously making my computer unusable and I'd really like some help!!

Here are my basic specs:

Windows Vista 32bit
Intel Core 2 Quad Q9450 2.66GHZ
EVGA nForce 790i SLI MOTHERBOARD
4GB 533MHZ DDR3 RAM
EVGA GTX280


Please help!

 

Hi

I thought I would also add that there may be clues to the problem in the event viewer.