Systemworks/Cleansweep question

Windows ME 4.90.3000, Pentium 4, 128.o MB Ram, 20 gig hd. (hope I did that right)

I have an older Dell and the Hard Drive only has 1.60 GB left. I have been cleaning and cleaning but don't seem to get anywhere. In the Clean Sweep portion of my 2001 Norton Systemworks there is something called "Unused File Type Finder". It says there are 23,539 selectable files in the archive, but I can't look at them because they are compressed. I never did register the WinZip, so can't use it to look at these files. Most of these files are in Folder C:\_restore\archive. I would love to delete these, but I'm afraid my computer sense is mostly non-existant. I need some advice!!

You might need to know that when I was in college, the computers took up a whole huge room and used punch cards. I'm trying to keep up, but there are some big holes in my computer education. Any help would be appreciated, and I have already uninstalled the Norton Anti-virus.