I have a Sony Vaio.
It was running like a complete dog until it I uninstalled one of the windows XP updates.
When I say like a dog, something like 15 minutes to start up, only one application could be run at a time, even then incredibly slowly.
I tried a variety of different diagnostic programmes but nothing showed up as a problem.
I eventually started uninstalling windows updates starting with the most recent first. Windows updates only, not the security fixes.
Unfortunately I don't remember which one (I made a note of the number, but have since binned it).
The one that caused the problem had it's hooks into every single component of the laptop. On re-booting the laptop XP had to reinstall every thing! (hardware only)
To be honest I thought I might have made a big mistake at first, but once it had 'found' all the hardware every thing was back to normal.
Not a single bit of data lost, running like it was when new.
I've since turned off windows up date...
