To save electricity and reduce the chance of surge damage I normally switch the electricity mains off after I've finished using it. Lately the PC won't switch on if I press the button, unless I let it sit for a while after I've switched the mains on - looking at the back of the ATX PSU, the light that indicates it's getting power flashes for several minutes before settling down to a steady glow, at which point it's possible to switch the PC on. Once it's switched on it's fine.
Any thoughts on what this might be?
If, as I suspect, it's the PSU itself that's on its way out, are the connections for ATX powers supplies completely standardised? The PC is an HP Pavilion, the existing power supply is a Bestec ATX 250 12-Z.