Sleep/Hibernate/Shut Down Not Working

I've had my Area 51 laptop (running Windows Vista Home Premium) for about 2 years now, and the motherboard crashed last month, so I sent it in to be fixed and I got it back a few days ago. I re-installed everything, it all works just fine, except every time I try to put it in sleep mode, hibernate, or shut it down, it comes back on in about 10 seconds. I've de-selected all the "allow this device to wake computer" and "allow computer to shut off etc. etc." tabs under power management in the Device Manager. I don't have a mouse or extra keyboard attached. It's not my wireless connection or card. It's not set to "wake on LAN" or anything. My power button isn't stuck or jammed. I don't have any timers or auto-updates set. I'm at my wit's end. Can someone please help me?

Sorry for the double post. I don't know why that happened either. T_T It's just not my week for tech I guess.

Hi Night_Terror, welcome to WTT. Try booting to Safe Mode then do a shutdown, see if that works. If yes, then something is starting at boot time that is causing the problem, software or device driver. You say you reinstalled everything, does that include all drives, including the Chipset driver? DId you use newer ones or the ones that came with the laptop originally?