Problem with an old backup

Hi! I don't know if this is in the right thread, but I need some help. I'm
running Windows 98(SE) on an old PC which only has 7 gigs of HD space. Awhile
back, I had to use my recovery disk to repair a huge problem. The problem
that cropped up afterwards was that I was cut down to 3GB of disk space. Is
there any way I can get rid of the old backup without damaging my system? I
finally got rid of the AOL virus, but something tells me there's quite a bit
of old AOL files in the backup along with everything else. The option I used
with the disk (LGIA Recovery Disk) was the one in which you don't completely
format. The backup is killing my system's ability to get the most out of my
DSL connection, which, quite frankly, stinks. If anyone knows of anything I
can do to repair this problem, please let me know. Thanks!