Blue Screen memory problem the last few days

[WatchTower]

I've been getting this blue screen up these last few days now and then what can cause this. I was wondering if it's my overclock but if it is why is it only effecting my PC now I've been using the my AMD64 [email protected] fine for months.

 

[WatchTower]

I don't notice an drop in performance and normaly in the past with older PCs I've owned I have notice a good drop in performance when things get to hot.

My AMD64 3200+ is clocked to 2.7Ghz and I have my Vcore at 1.45. Does that seem low for such an overclock?