microsoft.public.windowsxp.perform_maintain

I've been noticing that my computer is accessing things a bit slowly.
Sometimes it takes a second or two to switch applications and bring up
menus. After some use it can slow down much more than that.

I have just disabled write caching and things have speeded up
considerably. Is this a sign of a deep seated problem?

I have a 1.8Ghz processor and 768MB of ram.

Any help would be appreciated
C.T.