bootup stops at POST - stumped

Hi all

Firstly the machine:
Gigabyte s3-p965-s3 mobo, 3gbRAM, intel dual core 6300 1.86Ghz (not overclocked) , running XPpro with SP2, Nvidia GeForce 7900GS with 500mb onboard ram, 500GB HDD

was working fine until it was moved to another room, then on startup i get continuous short POST beeps and it powers down, before trying again without me touching anything. so far have checked all connections, removed, cleaned and reseated all cards, reduced amount of ram and tried again. cant find a POST error list for the mobo on the gigabyte website.

I'm thinking PSU, but its only a few months old (its http://www.maplin.co.uk/Search.aspx?criteria=blue storm&source=15&SD=Y)
any ideas?

 

Im thinking heatsink on the processer, check and be sure the heatsink is tight, just sounds like the thermal protection is kicking it off. ed

 

thanks for that.

Finally managed to find POST beep codes - its the power supply.