When shutting down windows xp.  I get this error screen passrv. exe what does it do?  I use regvac and a1 cleaner but, keep seeing this when computer shuts down.  Is this neccarrary or how do I get rid of it?

Looks like this is to do with an anti spam program you have.
I'm no expert, so look for more advice. You could also have a look at the site below for a bit more info. Good luck
Raimondo

PasSrv.exe - This process is with Panda antispam module, this is from Panda Platinum Internet Security Suite, for a secure system do not remove.
PasSrv.exe is made by a Third Party but is most likely safe

http://www.file.net/process/passrv.exe.html

:)  Thanks for your help.  I updated my panda to 2006 I don't think I seen it on shut down.  Will check tonight or whenever I shut down the next time.