OT: Brief help with this computer problem?

[onomastikon]

Hello folks, long time no hear -- I've been lurking now for quite some time, but am still enjoying Shrapnel et al. quite a bit.

I hope you will permit me a question, and I thank you in advance; I remember all of you, or most of you, as very computer-savvy people, and I am in a bit of a jam. I DLed and installed the HOMMV demo some time ago -- and what a surprise, I disliked it greatly. I think I tried it for about 20 minutes, then uninstalled. Got rid of the original DL (it was huge) and shortcuts.
However, I see now that in my "System" --> "Software" window (I run a German version of WinXP, SP2, so maybe it is called something different?), it is still there, still hogging up around 700MB. Sadly, when I click on it and hit "remove", it tells me that it is successfully removed, yet it isnt, it is still there.

This is alarming me. Can I do anything to rid it from my computer? Am I missing something?

Thank you much!!