How about starting over.
You can kill the partitions in DOS. I'll elaborate in the next post.
Pop in the XP cd, restart. When you get to the screen to partition & format - just set up ONE partition of 40g. You can do whatever you want with the other 120g after XP is installed by going to Disk Management.
If you have a floppy drive, you need a W98 (or ME) boot floppy diskette.
If you don't, it's a little trickier - you have to burn a bootable cd with DOS utilities on it.
Let us know.