Resolved Slower and slower ?

We have some computers in our forum that are getting slower and slower, both booting up and getting switched on to the Internet
Defragged. Cookies, Disc clean, Remove unwanted programmes, done all that, so what are the main causes of PC's slowing down and how do we go about solving the problem?
PC's (8) are about 5 years old, Windows XP home, 80 gb hard drives , used 5 mornings a week by over 50's.
Thanks. ( hope this is in the correct slot)
Spanner

 

Reply to Evan Omo, sorry I have not been back to you on this, our over 50's centre has been snowed in with blizzards and icy roads, so the Centre was closed until last Friday.
I should be able to get the info on Tuesday, let you know then.
Spanner.

 

I'd run Ccleaner on one of the machines to begin with. Then I'd run TFC on the same machine and see how that goes.

I'm assuming they're all identical machines.

 

Update on this problem of slow computers.
Local Council, who own the computers, have decided to uninstall Windows XP on all 8 PC's then re-install Windows XP, according to them this should speed things up.
We would prefer Installing Windows 7 but we do not have the pockets that has the money.
I think I will sign this off as resolved , and thanks to all for the advice.
Spanner.

 

If I were you, I'd try Ccleaner and TFC on one of the machines and see what effect that has - if any!!

After all you've got nothing to lose as they're going to be reformatted anyway and, who knows, you might gain yourself a few points if it solves the problem.