Creaping DEP syndrome

Hi,

i have a computer that has been running Windows XP happily for quite a while
now. It is fully updated from Windows Update.

My problem is that a few weeks ago, I encountered a DEP error that informed
me that WMI should be closed. I kept getting this dialog on startup until I
disabled DEP for WMI in the System Properties control panel applet.

Then a week later I started getting DEP errors on startup of MS Visual
Studio 2003. So I disabled DEP for this application.

Now today I started getting DEP errors for Internet Explorer 7. So I have
to disable DEP for this too.

This has me concerned because it appears that every week there is a new
application that violates DEP. Is this some kind of virus or mal-ware? All
of these applications have been running very well on this computer for many
months.

Any suggestions on how to stop the creaping DEP syndrome would be appreciated.