I've been browsing this site for a while and gotten some good info (thanks!) but have run into a problem that maybe you can help with.
About a month ago I built myself a home theater PC with the following pieces.
i5-2500K 3.3 GHz processor
Asus P8H67-M mobo
8GB Crucial SDRAM
Antec EA-500D power supply
Samsung Blue Ray drive
Samsung 1TB SATA HDD
Windows 7 Home Premium 64 bit.
Hauppage WinTV-HVR-2250 TV card
All of this is in a really cool nMEDIAPC WOODEN computer case (looks like a 1940's radio).
I've been really happy with this system until yesterday.
Turned it on and it was working fine for about 10 minutes, than it shut down with no warning and after a couple of minutes tried to restart on it's own. It did that at least half a dozen times, only once or twice getting as far as Windows trying to start. So I shut it down and pulled the plug and let it sit for an hour. When I restarted it the thing started normally and ran fine the rest of the evening... about 4 hours.
Today it's behaving the same way, it started, ran for a few minutes and then began restarting.
It doesn't seem like anything is getting warm, all the fans are spinning properly (including the one on the back of the PS).
I'm thinking (hoping?) it's the power supply, but this is just weird. I've seen systems behave sort of like this before, usually older ones with bad caps, but this thing is virtually new, and as I said last night it behaved perfectly after it finally got going.
Never got any response but I figured it out and the answer might help someone else.
A while back I put a new 750 watt PS in another system and the instructions were quite insistent about using the supplied power cord. My new system has a "green" power supply (I think it's green because it's painted green and it came without a power cord).
Well the first time I powered that rig up it acted strange and then the power cord started getting hot.
Remembering that I checked the power cord on my HTPC and it was awfully light. So I swapped it for a heavier cord and... the machine has worked perfectly ever since.
So, if you have weird problems start with the basics, beginning with your power cord!