I have a slightly odd problem. My PC worked for for about 18 months, but recently, after suspending (or hibernating) if I press the power button (once) or a button on the keyboard, the keyboard lights come on as does the mouse - but the PC itself doesn't wake from sleep. I have to press the case power button for 5s or so - often 3 or 4 times and then the PC starts and resumes correctly. I think this means it's something to do with the PSU - but after resetting the bios and doing all other checks I can think of, the problem remains. Rather strange and I have run out of ideas (other than installing a new PSU but I don't have a spare one just to try). Any other suggestions?