Fine? its 145+ in there 5 more degrees and it will go kaboom
mah processor is AMD 2000+ 1.7 GHz
If it reaches 145C, than it is way to hot.
Id say check if everything on the inside is clean from dust.
Dust will glog up after a period of time of using a pc and increases tempertures.
If it is clean from dust bunnies, and the problem still exists, i think the termal paste between the processor and heatsink is dryed out.
Buy some new thermal paste, artic silver is a good brand.
Take of the heatsink, clean the surface of both the heatsink and processor.
Put some new termal paste on the processor and place the heatsink on it again.
Most likely that will solve your problem.
[edit]
Btw, that processor is like 8-9 years old or so.
Dont you think its time to upgrade?