Several issues, possibly related?

Hello there

I'm having some issues with my system, running Win XP, SP3. This might take a bit of explaining.

A bit of background first: I had malware issues accompanied by an odd problem where my PC wouldn't shutdown properly. The fans remained running once it was turned off and the red LED kept flashing. I suspected this was connected to the malware & would be resolved once said malware was removed. Malware was sorted out (thanks to majorgeeks) but shutdown issue remained, plus resident experts advised me it wasn't malware related & I should post about it in the software forum. That's what I'm doing now.

More info on shutdown problem: computer closes as normal, no error messages. It progresses to black screen and monitor turns off just as it would ordinarily. The only problem is that the fans stay on and the red LED does too. It doesn't matter how long you leave it for - the only way you can turn it off completely is by turning it off at the wall. If you turn the power at the wall back on, the fans & power LED come back on immediately.

Also worth noting, once you put the computer into psuedo-shutdown, you can't turn it back on. The only way you can restart it is by turning it off at the wall, turning it back on at the wall & then pushing the start-up button as usual. If however, you do Start > Turn Off > Restart within Windows, the computer restarts as it would normally.

Since my computer started doing this (over a month ago now) I've noticed a few additional problems cropping up. First, about a week after my shutdown problems started, the computer stopped recognising my wireless keyboard USB receiver. Now every time I start up, I have to unplug & re-plug the receiver for it to be recognised. Next, my wireless internet connection started playing up. In order to connect to the internet, every time I start up I have to flush DNS and then register DNS. If I don't do this I can't load any sites, even if I have a good signal!

My hope is that someone recognises these seperate issues as all pointing towards one single problem. My fear is that I've just developed three unrelated problems all in quick succession.

Sorry for the long message. If anyone can shed any light on what might be causing this, I'd appreciate it. I've tried Googling for the individual issues but I can't get any clear solution & I'm hoping they're all related anyway.