Audio problems on my Mac. Help!

[Belroi]

Hello people.

I'm having some problems playing audio on my Mac.

Every now and again, the audio will start to go slightly crackly - like static on an old record. This gets worse and worse until, after a minute or so, it ends up as digital noise. After that the audio gradually fades to silence.

This can happen on any application: iTunes, Safari (YouTube etc.) and Logic. It's more likely to happen when more than one of these is open at the same time.

A bit of background on my machine for you:

It's a 1.25 GHz Power PC G4. 1mb C3 cache. 2GB DDR _SDRAM. OSX 10.5.1. And I've got a second internal hard drive which I use to record audio in Logic.

Also, my machine now tends to freeze from time to time. The only way out being to turn off and on. Not sure if that could be related. It's more likely to do this if I leave it unattended for a while.

I recently wiped both hard drives and started from scratch to see if that would sort things out. Now there is very little software on my Mac at all, but the problems keep happening.

Any ideas?

This is driving me mad so any tips you could give would be very gratefully received.

Thanks very much!

Lee.