What do you want to backup specifically?
The four options it gives you are:
- My documents and settings --> will backup your "my documents folder" and all settings associated to your account.
- Everyone's documents and settings --> as above but for all accounts on the computer
- All information on this computer --> The entire c drive (the longest backup option)
- Let me choose what to backup --> choose what you want to backup (e.g items on your desktop and a particular folder on the root of c
Once you have selected one of these options you will then be given the choice of where to backup to. Make sure your external HDD is plugged in and then choose that from the menu. Don't even attempt to backup to A: (you'll need a lot of floppy disks
Finally, whatever backup option you choose, it's not advisable to use the computer until complete...