You do not need another zip program as windows xp has unzip build in? Are the extensions of the files.zip? if so then i am not so lost because you get it with windows and it should not expire.
What happens if you right click a zip file can you extract it?
winzip and winar eventually come up with the obligatory popup. but i really see little problem in clicking continue. in fact let me say this is true for winrar as i now realise i haven't used winzip in years.