whats ur system specifications?
also, see you dont have too much on same wire on which u have plugged in the PC, like other electronic equipment.
Intel Core2Quad 2.66Ghz 12MB L2-Cache
4096MB DDR Kingston Hyper-X
XFX 9600GT AlphaDog
Seagate 2 X 320GB SATA2
LG L246WH Flatron 24"