Account is topped up, still beeping.
The inside of the computer is actually very clean due to my pressurized case design.
I have two case fans drawing filtered air into the case which then exits through the various openings, different to the norm where air is drawn in through various openings usually leaving dust buildup on things like CD/DVD ROM drive doors and volume controls and inside the case itself.
I did have an issue with the processor overheating a while back apparently due to the heat sink paste drying up. Cleaned it up and applied fresh paste and that seems to be ok now.
I will probably get around to building a new one soon, but it's been a while and I'm a little out of touch with what's hot in components these days.