System unstable please help

Ok I'm at a loss as to why my system is so unstable and hope you guys can help. I normaly run 5 EvE accounts with no issues cpu normaly around 50% load at max demand during gameplay. When I go to my full 7 accounts my cpu is at 80% with game idle but if I do anything it goes to 100% and shortly after my system will crash (auto protection kicks in). RAM never goes over 50% usage, and my video is stable at 45 fps for my main and 15 fps for the alts. I run it with two 23 inch monitors configured to have one monitor for the main screen and 4 or 6 smaller clients on second monitor depending on amount of accounts I have active. My system is a

Intell i7 CPU
16G Tripple chan ram
Duel GTX 460's with 1g ram each (Only using one video card though)

With what I have seen around the forums a system like mine should handle 10+ instances with no issue but I'm not that good at troubleshooting this sort of thing please help.