Can't open Nero

Just started getting this message yesterday: “Your window version is outdated and nero cannot be run. Please update your windows version using the patches available at”
I am using Windows 2000 with latest service packs and updates. This message started showing up on on the latest 5.5 version. I updated the the lates 6.0 version and still get the message. The only thing I can remember doing is un-installing Alcohol 120. I’ve tried the nero web site and can’t find anything. Any help would be greatly appreciated.

Are you using a full version or a demo?

I am using the full version. I ended up just re-formatting my computer and reloaded everything. Not sure what caused the problem, but it’s working ok since the re-install of everything.