Backups are like car insurrance: they're pretty damn important.

I recommend Acronis (True Image 7.0) Backup Program.
http://www.acronis.com
US$50.
Very simple to learn.
About 22 MB, you can download it on-line (if you have a credit card). It'll run in the background just fine while you chat on Mudcat. If you only have one disk, you can ask it to set aside a section of your disk as an unreachable special backup zone (in Linux format, I think) which Windows viruses will have a very hard time attacking. It only saves full disk-partition images, but you don't have to restore full partitions (to restore only selected files, you can load any full backup or incremental backup as a disk image and then simply copy the files you want from the selected backup -- that's the sort of thing to do when someone has messed up your system: crawl through your incremental backups until you find the one without the bad program, then restore that entire disk image (to get the system files just right), then restore any subsequent data files you want from subsequent incremental disk images.) I've restored my system twice and my dad's system about a dozen times with this program, without any problems.

More cheaply, if you only have Windows98, you can effectively backup your system with XXCopy to back up files, and LFN (long file names) Tools
to restore your long file names from within DOS. After Windows98, simply re-copying the files into place isn't enough to restore your system.

Never keep your backups on the same disk partition where the originals are stored (Acronis won't allow you to - you must create its backup zone if you have no "D" drive). Preferably, keep them on a different disk. Best of all, move copies to another site occasionally.