cannot uninstall software

Kelly called our radio show and said he was unable to uninstall some software from Windows Vista.

Try to do it from Safe mode...

If that doesn't work, you could consider using System Restore:
Turn back time on your PC
What is System Restore?
System Restore: frequently asked questions

unable to uninstall (antivirus) software

Frank called because he was unable to uninstall his antivirus product...

My suggestion is to try to uninstall it from Safe mode...

Symantec has had removal information, and tools, available on their website...

uninstalling programs

Paul has a computer that came with Norton 2005. He wants to uninstall it, and install a different (antivirus) product.

How to change or remove a program in Windows XP