Help with new computer build issue...

Hello all.
I am having a problem with a new build that I put together for my wife. It is nothing fancy, an ECS A770M-A motherboard, AMD 64 X2 4800+ processor with 2- 1gig Crucial Ballistix Tracer memory. When I first built it, it was fine for about a month, then it started acting up by not wanting to awake from hybernate mode and then getting to the point were it didn't want to start at all. Everything would be running, but the motherboard wouldn't post and the hard drive would not spin.
I figured somehow I got a virus, so I bought a new hard drive, since the old one was ancient and loaded a fresh copy of Windows XP Home on it. Seemed to be working fine for awhile, so I hooked up the old drive copied some pictures that my wife had on the old drive. After that McAfee started to pup up that it had found PUPs did I want to delete them? I figured this was the problem before and it never recognized them so I said yes. The programs it found were both in system32/tools folder one was restart.exe and one was hide.exe. I later found out by research that these were programs put on by the motherboard manufacturer. I reloaded all the drivers that came with the motherboard hoping it would fix the problem. No such luck.
So the point I am at now is after going to sleep, the computer will not wake up unless I turn the power supply off and then back on. After doing this everything is just fine. What do you all think might be the problem? I was going to just RMA the motherboard, but I bought it as an open box and can't return it. Any help would be greatly appreciated. Sorry for the long post, wanted to get all the information in so nothing was missed.

Thanks.