Weird System Freeze

Hi, I built my computer about a month ago, and recently (I would say the past week) there has been a weird problem. The first time I turn on my computer of the day, (usually the morning 10am-12pm) after about 10-15mins of use, my system would freeze for about 2-3 minutes. I can have WMP on the background and it would be fine, my mouse can move, but I cannot click on anything other then my desktop gadgets (I only use 3 btw). After the 2-3 minutes, it would unfreeze and the system would be fine for the rest of the day until the next day. Pretty much it freezes once a day, even though it might not be a big deal, it really bugs me. I have tried testing my RAM, did an hour of Prime95 (I'm pretty new to this and pretty impatient =X) and haven't found a problem. Here are my computer specs if this help.

Intel i5 2500K
ASUS P8P67 Deluxe
G.Skill Sniper 8G DDR3 1600
EVGA GTX 560Ti Superclocked
Corsair HX 850W PSU
Antec 902
Crucial C300 64GB SSD
Samsung Spinpoint F3 1TB HDD
ASUS 24x DVD/CD Drive
Windows 7 Home Premium 64-Bit

Also some additional information:

It seems to me this happened after I played around with OC my CPU. I'm not sure if I did the right thing but, I OC my CPU to 3.7GHz at 1.2 voltage. My RAM is correct too, 1600 9-9-9-24 at 1.5 voltage. Both these Voltages are set manually. I'm not 100% sure if this is the problem, hopefully not. Also my system is on stock cooler, idling around high 30s low 40s and 50ish during load.

Please someone help me out, the next step for me is to reformat my system which I don't really want to do =[. I've also tried swapping my devices from the SATA ports, I hope that solves it.