Here's how I used to perform backups in W98SE:
I had a spare drive that was the exact same size as my main hard drive. I temporarily mounted it as my primary drive, and partitioned and formatted the spare drive, as well as making it bootable via a floppy disk.
After that initial task, when I wanted to do a backup, I hooked up the spare backup hard drive as a slave. Then I simply used Total Commander (aka Windows Commander) to copy the primary hard drive contents to the slave in verbatim. Anytime I wanted to perform a new complete backup, I erased everything on the slave, and copied everything over again using TC.
If I ever had a hard drive failure (actually, that happened two times), I simply removed the dead primary drive, and popped in my spare backup hard drive (as a master), and all was well with the world again 😀
To make things even easier, you can install one of those removable hard disk caddy/bays as a slave, and that makes it a snap to pop in your spare backup hard drive... if everything is set to "auto" in BIOS for the hard drives, it's simply a matter of powering down and back up again 😀
One advantage to al of the above is if you need to quirckly access a file from the backup hard drive (e.g. you've accidently deleted or overwrote something), you can easily snag it from the spare backup hard drive (quite a bit easier than when using any regular backup software).