Hey all.

Been having this problem for a long while now. Just started up suddenly and can't remember if it occurred after installing a software or if it's something hardware related. Any help is appreciated.

Problem:
After I shutdown the computer, maybe 2-3 minutes later, all the fans (PSU, CPU, Rear + Side case) start spinning; the hdd led flickers; and if my speaker system is on I can hear a flickering sound on there too (kinda hard to explain the sound). This continues for about 8-15 seconds and then it all stops, then after another minute or 2 it starts up again and stops. This continues unless I turn off the PSU power switch.

Also, the rear case fan (think 80x80, it's the smallest size that'll fit since there's 2 mounting hole levels above that one) went out yesterday after I air cleaned the system. I went and got an Arctic Cooling 12 PWM fan to replace it, but the connectors seem to be totally different (Arctic seems to use 4 pins while I can only see 3 pins on the Mobo) so that one doesn't work. But a while later I retried the rear fan and it seems to work for now. Dunno if something was lose of it it is truly dying.

I don't know if it's my Mobo (ASUS K8N) or something else. Only things I've upgraded since I purchased this system about 4-5 years back, was the ram. Upped it from 1 GB (2x512) Kingston Value Select to 2 GB (2x1GB) OCZ Platinum.

Again, any help is appreciated. Would go for a new system if I had the cash but least for another few months, at the earliest, I'll have to wait.