clean computer still freezes

Hi
I keep my computer very clean, removing temp files, cookies etc. regularly defrag and scan for viruses but it still freezes.....very frustrating!!
IE7 quite often does not respond, I have removed all add ons.
What could be causing this?
I would appreciate any help

 

You can start it up with the case open and check that all the fans are spinning freely. There might be a fan on the graphics adapter and also check the air flow coming out of the power supply.

Has the dust been cleaned out? Loosen any build-ups with a straightened paper clip, take it outside and blow the dust out (using a hair-dryer). Check vents and around fans.

You can check in Task Manager and see if readings are changing dramatically (use booting to blank desktop as a base).

Can you reproduce the freeze? What sort of activity causes it (for example, graphics based or disk intensive programs).

Matt