Data Execution Prevention (DEP) stops svchost

Archived from groups: microsoft.public.windowsxp.security_admin (More info?)

I have started getting Data Execution Prevention messages for Generic Host
Processes for Win32 Services when I start my PC. Later, when I try to access
certain folder functions (and other browser activities, randomly) I get a
long delay often followed by a svchost.exe access violation trying to write
memory at 0x00000000. It would seem to me that some process is misbehaving
but since DEP is preventing it from running, I can't find out what is
happening. I have run the latest virus scans (Symantec Corp Edition 9.0) and
have hardware firewall. I don't think disabling DEP for svchost.exe is wise
at this point.

I am running XP Pro SP2.

Any help would be appreciated.