I have one hard drive that has been partitioned into c and d. I have everything on c...but when I try to reformat d...it says it is being used...Will I have to reinstall xp? That is when the original partitions were created.
In XP you can run the mountvol command on the commandline to unmount a drive:
If this doesn't work, the error may give you a clue as to what process(es) have the drive open.
The two most likely culprits that could be holding you up are System Restore and the system pagefile.
By running through this process, you make sure that Windows isn't responsible for holding your D: drive hostage. If it still doesn't let you reformat the drive, another program may still be active on the drive.
If you are sure you have nothing on it that you need, I would recommend you download and boot in to Gparted.
From here, you will be able to either just reformat the drive, or delete and extend your primary c drive and make one big partition using all the available space.