^^dude ... i have never done all this.. anywhere ... i can get exact instructions.. how to do this cleaning?
Yes boy for the first time its very tricky to remove a stock cooler of old Athlon 3500+ from MOBO its releasing leaver is very stiff.
BTW if wanna try to do this. First remove side pannel of PC's cabinet. Now use a wide tip screw driver to push the releasing leaver from C shaped formation side. keep that in mind the tip should be wide enough to stuck in that but should not touch the motherboard. Now push it gently downwards thenafter sideways heatsink will be unlocked.
Taking out processor is rather simple afair use its releasing leaver first sideways then upwards unmout the processor.
Rest of the prosses is well explained by other forum mambers.