If you use Microsoft NT's backup without a tape drive, doesn't it default to a disk backup?
I ask, because it's been a long time since I used this utility!
There are various backup utilities "out there", but my favoured solution for a workstation is to use Norton's Ghost software to create a compressed image of a workstation. It will do this to disk, provided the disk or partition is separate to the one you are imaging.
I usually send my images to CD - there are some great deals to be had on burners!
Hope this helps