I have never done this as you get issues such as you have posted here. I do a clean install of XP as I have found it creates less problems and takes less time to do a clean install than sort the problems out. As well as not leaving bits and pieces from the old machine on the hard drive.
Only suggestion I would normally have is to boot from the windows CD and repair the XP installation but since you have neither mouse or keyboard I think you are stuck and will have to do the clean install.
Perhaps someone else will come up with some sort of solution but without either mouse or keyboard I cannot see what you can do.