PC that refuses to power on?

[notsobig]

Hi, all. These days my pc refuses to power on once I switch it off completely, for about 10 seconds. I don't remember exactly when it started happen but I think it's getting worse and worse. I mean I remember when I built this pc a year ago, PSU was quite responsive to power switch and it powered on almost momentarily at all times. But now it takes ages for it to power on especially after I strip things out and put things back together. You won't believe me but sometimes it takes as long as 1 minute for it to respond to power on signal! But once it powers on, everything seem to work normal, no sign of errors at all and I can play games for hours. And it always power on immediately in the morning which makes things more difficult to understand. So what do you guys make out of this strange symptom? Do you think my PSU is dying or what? BTW, while it struggles to power on, I noticed my keyboard lights(num lock, caps lock and scroll lock)and webcam light are flashing randomly. I have rebuilt this system numerous times (for cleaning) but that didn't help either. BTW my PSU is antec neopower 480 and I have already requested RMA and waiting for a reply from the antec support desk. Do you guys think new replacement PSU will fix this problem? Thanks.

[MSIC]

It's the first thing i'd do.
If that doesn't work, next on the list would probably be a motherboard RMA (although it could be almost anything!). Also run memtest on the RAM (but those symptoms don't sound RAMmy to me)

PS Things that are changed by time, as in your case, suggest heat build up (and then expansion) followed by a period of cooling (and contraction) when powered down. You can test this theory easily by pulling the case sides off, and directing a powerful (cool) fan at the insides, making sure the room is fairly well ventilated. It may work, it may not make a difference, but it's another thing to try.

[notsobig]

Thanks MSIC, I hope it's not motherboard I love this board and I don't think gigabyte make this model anymore. I personally think rams are fine because I can run prime95 for more than 12 hours. And once it's powered on everything run flawlessly and I sometimes keep my pc running for 2-3days straight, without single rebooting. It's just when I try to power on my pc from off state, that it struggles. I don't know why. And I'm afraid my pc is well ventilated(3x80mm intake fans and 1x80mm(top) and 1x120mm(back) exhaust fans) so I don't think it's heat related. Thanks for your suggestion though.

[notsobig]

Got my new OCZ PSU today and problem solved. Never thought big name like Antec would fail in one year... but I learnt my lesson, bah!