Corrupt old Home install will not allow install of PRO

[trevlac5]

I have purchased a number of avast! 4 Pro licenses and am having trouble on a win98 machine. I know that I can just enter my registration key to upgrade from the Home version because I've done that on other XP machines. This one gives me the error "This program has performed an illegal function and will be shut down...". So I tried to uninstall it from control panel - it gave me the same error. I tried to install the downloaded Pro version - same thing.
How can I remove all traces of the Home version?
Because I need an AV prog on the machine now I temporarily installed another one from Computer Associates w/o a problem.

What are my options?

[Vlk]

Try to uninstall avast! using the AvClear4 utility, restart - and then run the Professional Edition installer again.

Hope this helps,
Vlk

[kubecj]

Huh, that's the very first time I've heard about such behaviour.

Is it possible that the file setiface.dll is broken, ie. it doesn't match file setiface.ovr?

Also, you should be able to run the installer to correct the problem.