When I Googled "Dual DVD Copy Gold" I found many entries, pages and pages of them, but mostly from crack sites, keygen sites and torrent sites, none of which I would touch. But I did find a post that described what it did;

"Dual DVD copy Platinum can copy DVD movies, including copy protected movies, on Dual Layer DVD disc and fit DVD movie to single DVD disc (DVD to DVD, DVD to Video CD, DVD to AVI).

Dual DVD copy Gold copies DVD movies (DVD to DVD, DVD to Video CD, DVD to HDD) supporting most popular types of media and video formats.
".

So it looks like this is software for copying DVD movies including copy protected movies.

I am unsure why uninstalling that would have caused your XP to become so unstable, and neither am I sure why there would be 3 GB of files associated with it, unless you have used it to copy DVD films and these files are the 'cache' of those.

So, I'm a bit confused with what has happened here. But an option for you.

Can you still use your Start Menu? If so, go to Start > All Programs > Accessories > System Tools, then find System Restore. If that opens, find a restore point in the calendar that exists before you uninstalled this software, and restore the system back to that date/time. See if that returns the system to working order.

If it does, then with the system working again, explore that DVD copying software to find the developer's web site, (often in Help > About), and visit the site to look for guidance about how to uninstall the software.

I hope that helps.

Mark