SP2 Time Delay

Hi,

I am re-posting this problem, as it seems to be effecting other people I
know with XP SP2 and I received no sensible answer last time.

So, to be clear about the problem:

When I right-click on an icon (even a <1kb text file) the pop-up menu can
take up to 30 seconds to appear.

When I select a file (any file, regardless of size) and press the "DEL" key
on my keyboard, it can take up to 30 seconds for the "Are you sure you want
to delete this item" dialog to appear.

When these things happen, sometimes the open folder's title changes to "Not
Responding". After about 30 secs, it all returns to normal and I can carry
on.

This all happens at about 10-15 minute intervals. Starting up other
software (especially MS Office 2003) is also slow, almost locking up the PC.

Everything was okay before installing SP2.

Yes, before anyone tells me (yet again), I have defrag'd the disk, and run
anti-virus software, and run disk cleanup, and uninstalled and re-installed
SP2, and I have all the latest drivers.

Does anyone know the ** real ** reason this happens, and if so, is there a
solution? It's obviously a SP2 fault, but is there a work-around for it?