1. no such thing as a i7 2500k XD
2. 1tb or MEMORY? or storage XD memory is ram.
to answer your question, its probably the PSU but it could also be because you are using too much power in one area in your room.
btw, do you know how many watts your system uses with your specs? im curious because i wanna get sli gtx 560 tis and i wanna know if 700W would be enough, probably not though.