W7 Sleep Issue

Hi folks, just looking to pick some brains:

I've an old Abit P35 mobo here running a media pc under W7. It's developed an issue which I've noticed through putting it to sleep mode. It'll go to sleep fine (it's been running fine for years), but it won't wake up. IN fact, I think it's suffering a power loss upon entering sleep mode, as the only way to sort it is to press the power button on the case, where the pc boots from cold with a "windows didn't shut down properly" message. None of the power settings in windows have changed, & none in the bios either. No new software has been installed since this started happening.

Prior to this, the VFD on the front panel (it's a Silverstone LC-20 case) was getting garbled text displayed, so I figured maybe the VFD had gone faulty, and today I disconnected it. The problem still remains. However now, a new problem has arisen. Now the red led on the mobo pulses when a/c power is connected, and the system won't boot. If I press the power button when the red light is on (it pulses on & off), the system will boot. I think this is the 3VSB led). It still won't enter regular sleep mode though.

I've enabled hibernation mode now to maybe get around the problem, but once I enter hibernation mode the red led will start pulsing again & the system won't resume via the remote/keyboard anymore (it used to do this from regular sleep mode). I can power the system on again using the front switch, and the system will resume from where I left off via hibernation mode.

Any ideas, I'm thinking psu or mobo fault...more so the psu?