You'd have to use DBAN as Eraser doesn't wipe the hard disk, it only wipes files and cleans free space.
Here's a few things to remember.
1. Backup any data you need on a CD or ZIP disk.
2. Make sure you defrag your hard disk before performing a DBAN wipe.
3. Delete any info you don't want anyone else to recover by using Eraser. You might want to use the Gutmann method. Open Eraser and hold down CTRL + E and select Gutmann if not already selected.
4. Insert your DBAN floppy and hit restart. (Make sure any Windows/Linux CDs that are bootable are out of your CD-ROM)
5. After you have reinstalled Windows make sure you use Eraser to clean up the unused free space.
Everything there apart from #4 is optional so you don't have to do it but I'd advise you do it if you a paranoid PC nut like me.
