I know someone's gonna post over me with this, since I still consider myself a novice, but I'll give a shot at it.
When do you notice this happening? All the time? If you have something like 128MB of memory, and a non-continguous paging file (a Windows-managed swap file, always being resized), this might cause this. If you have a couple of IE windows open, some programs open, this'll cause your hard drive to thrash from the need of more memory. So, it turns to your hard drive for virtual memory.
A way to deal with this is to set your paging file to a set size. If you have space, I'd recommend 500MB. This Microsoft page should be enough, since it includes links on the steps to configure an optimum paging file for you system.
<A HREF="http://support.microsoft.com/search/preview.aspx?scid=kb;en-us;Q314482" target="_new">Configuring the Paging File(s) for Optimization and Recovery for Windows XP</A>
If you have two hard drives, I'd create a partition for the HD without Windows XP, so that it's at the very beginning of the HD, just enough for it's size. That way, it won't get fragmented, and you won't thrash from a paging file that's resizing.
Option 2: Get another stick of memory.
Someone tell me if that's a good explanation. I wonder how well I sound at explaining this. :lol:
<font color=red><A HREF="http://www.geocities.com/btvillarin" target="_new">My Windows XP-based Website</A></font color=red>