Missing start up files

I recently deleted Norton antivirus 2001 and now I get this message when I start my system.
The system has missing files C:\programs\symantec\symevnt.386 and
c:\programs\norton\navap.vxd

I tried installing a newer version 2002 and it says the old one is still on the system but when I try to unistall again (2001 still shows up in Add/Remove programs) it says Unable to locate Program files/Norton Antivirus/nav95.isu Unistall not completed.
Please Help.