If you are running XP in NTFS, a DOS boot floppy won't do much good. DOS 7 - well, any DOS - can't see NTFS partitions. Try a Knoppix Linux on CD boot disk.
If XP is running in FAT32, you can use DOS 7.0 or 7.1 (Win95 OSR2 and Win98SE DOS) to do things in the hard drive. Download them from a boot disk site.