In a perfect world all software would do incremental backups of your work. Most don't, however.
I'm crazy when it comes to backing up, and I love to brag about my backup scheme...programs can be replaced, your original work cannot. I cringe whenever I see people running one hard drive on their system, with all their eggs in one basket, so to speak.
Check out a program called Syncback, there is a free version as well. You can schedule timed backups, every few minutes if you want, of any folder or file on your system.
My backup scheme is:
1. Two separate hard drives that contain data only, separate from my main OS drive, and I use Syncback to synchronise the files on them.
2. Get some sort of drive imaging software, I highly recommend Acronis TrueImage, it has saved my ass countless times. Don't rely on XP's lame system restore...
3. Make a Bart PE disk (
http://www.nu2.nu/pebuilder/). Hardcore, yes, but it gives extra insurance against the "worst case scenario".
Good luck
Oops and I almost forgot, get an uninterruptable power supply for your PC, just do it, NOW.