Trouble installing trend micro after symantec AV

Hello,

We have recently rolled on Trend Micro worry free business server/client solution to an client that did not have an anti-virus for some amount of time. Some of the computers had a symantec client anti-virus, and of course to install trend micro you have to remove the symantec client. I could easily do this on any of the windows XP or Vista machines, but when it came to two windows 2000 machines symantec would not come off. The first step I tried was to let trend micro remove symantec and it didn't work, then I tried add remove programs that didn't work either. Then I ran the NONAV from http://ca.huji.ac.il.mcafee/Nonav.exe and that did remove the symantec I could not find any trace of it on any of the two systems. But when I went to install the trend micro client on the machines, it still tells me symantec anti-virus 8.x is still installed and trend micro cannot remove it and to please uninstall manually. At this point I went to symantecs site and looked at the instructions to remove the client manually, but of course when I went to do this there are no traces of it in the registry or program folder. Any ideas?