System restarts

[BlueCell]

OK have some patience cause this is a long story
I purchased a Mobo combo Asus P5VDC-MW,Intel 945D dou core,Atlas precison ram DDR2 667 512MB,Thermaltake copper heatsink/Fan, and a coolmax 550w power supply. When I installed this hardware on a HD with programs on it i got a M.C.A..(i dont recall code). So i erased the hd and tried again this time the system woudnt start. RMAed the combo and was told MoBo combo worked fine. Ram was swithced but retailer didnt know why. Installed combo Again and got frequent and random restarts. Paid good money to GEEK SQUAD to tell me they dont know whats wrong(NO REFUNDS).
Installed hardware again with programms on HD and got another M.C.A.. I then got a new case with 3 120mm fans A new HD,Radeon 1650pro and assembled it all again now i get frequent and random restarts again. System restarted while loading Windows XP home. Plus when Geek Squad tried other types of RAM the system would not give them video (only the Ram that come with it will work in it). Im tired of spending money for Techs to tell me "I dont know". Anyone have any ideas i could try besides throwing this system out a window and watch it break into pieces

 

[ru1thirst]

Now take this for what it worth. I've only put together 2 machines in my days but I've read forever. With these types of problems I've seen the culprit be: a faulty or too weak of psu. Do you have a friend or another maybe stronger psu? 650-700? Also not sure what bios features you have but maybe try checking to see if it is set to system or safe default. Sometimes if in Optimized setting, problems occur. Also run a check online on the timings on that exact ram and make sure they match the bios settings.

 

[BlueCell]

Thanks ill see what i can do i dont have another PSU ut ill see what i can scroung. also not real confident in messing with bios,but i guess its time to start. thanks for the tips....i welcome any other ideas to try if anyone has one.
BlueCell