Is this a motherboard issue?

[Warpspasm]

Lately, I've been having a problem that I'm thinking is a motherboard issue. If I leave my PC on all night and it hibernates, sometimes it won't come back on. I'll push the on/off button, and the fan will power up and the optical drive and case lights comes on, but won't go past that. At first, I thought it had something to do with Windows7 and hibernation, but now I'm not too sure. The problem now happens intermittently when I actually power down and turn off the PC normally and try to reboot. I never even see the post screen. It just powers on the hardware (at least the fans and case light) and sits there. There have bee a couple of times when I had to manually turn off and on the switch a couple of times to get it to post and boot. Again, it's an intermittent problem.

Here are my specs:

Operating System
MS Windows 7 Home Premium 32-bit
CPU
Intel Core 2 Duo E4500 @ 2.20GHz 37 °C
Conroe 65nm Technology
RAM
2.0GB Dual-Channel DDR2 @ 399MHz (5-5-5-18)
Motherboard
Gigabyte Technology Co., Ltd. P35-DS3L (Socket 775)
Graphics
L90D+ D-SUB @ 1280x1024
512MB GeForce 8800 GT (EVGA) 60 °C
Hard Drives
156GB SAMSUNG SAMSUNG SP1614C ATA Device (IDE) 29 °C
313GB Seagate ST3320620AS ATA Device (Unknown Interface) 33 °C
625GB Western Digital WDC WD6400AAKS-00A7B0 ATA Device (IDE) 33 °C
Optical Drives
ASUS DRW-1814BLT ATA Device
PLEXTOR DVDR PX-712A ATA Device
Audio
Realtek High Definition Audio

Thanks.

 

[Warpspasm]

Nobody has any advice on this one?