had the same spec pc for abouta year then one day it just black screened and the headphones started to buzz for about 5 seconds, then they stopped, screen showed "no signal" message and i have to power down, wait a few seconds then power back on to fix it.
i got a new GPU as i thought that was the problem, new one is geforce 8800 gt, still happened
so i got a new PSU as my old 1 was 305. new one is jeantech 500watt...still happening
it happens at diffrent times on diffrent games, and never if im not playing one
WoW can be, 1-2 hours
MW3, normally 5-30 mins
dawn of war 2, 3-4 hours (only happened once)
pc specs are:
CPU AMD athlonx2 64 7750 2.7G i belive
I had the exact same thing happen and after much aggrivation and trying a host of different things I found that it was the sata 3 port that my SSD was connected to and in specific the Marvell controller. I moved the SSD connection to the sata 2 port which is controlled by the Intel chip and the problem dissapeared. So I would suggest trying a different sata port.
It all depends on the drive that has the OS on it , so if you have that and it was connected to the port with the Marvell controller then you want to make sure that it's connected to the port with the Intel controller. Usually thats the sata2 ports.
That is odd that this problem came about after you moved , also odd that it is decribed just like the problem I was having. You say that you have a new psu and it is 500w and that the video card is a GTX 8800 so the power supply should be enough. If you just got it maybe it's defective and you could then do a RMA.
Although like you said the only things you haven't changed are the keyboard , mouse , headphones and monitor. Do you have anyone you could borrow thier keyboard and mouse just to see if by chance it is one of those parts?