If it's a "full version" (as opposed to an upgrade version) of XP, I would delete the XP o/s partition, and recreate it (and reformat, of course).
Put the disk in, and restart the computer.
When asked, Press "R" to repair a Windows XP installation using Recovery Console, and it will give you the partitions as numbers, like:
1: C:\Windows
(so you type a "1")--just type the number corresponding to where your Windows folder is.
Then you can issue "DISKPART" command to recreate a new O/S partition
("Delete" the partition / "C"reate a new partition [and allocate the space]).
Then what I do is format the drive, at this point.
Ask for help if this sounds vague.
But, I do not think you will need a driver, before hand. There is a key to press to install 3rd party drivers on XP (I think it's "press F6 to install a SCSI or 3rd party driver")....but you don't have an SCSI drive, I'd be more than willing to bet, so just try loading XP again.
Was this XP Professional?
Sometime, you WILL need to download from Toshiba "Drivers" (and "Initial Programs", if you want them).
http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/modelContent.jsp?ct=SB&os=&category=&moid=1757705&rpn=PSAD0U&modelFilter=A135-S4656&selCategory=2756709&selFamily=1073768663
to install after a successful XP installation, so download all those drivers, and burn them onto a CD (or DVD).