there is normally a hidden area (look in disk management to see) containing the files you need.
this next sounds a little far fetched ... but it's true - honest
some versions of Vista upgrade gives you the option to ununstall back to XP
(buy you would have had to tick the box) look in add remove progs ... you might ......
otherwise ... it's time to contact the manufacturer and stamp your feet ... they will eventually cave and send you a disc.
Alternatively ... on the underside of the lappy there should be a licence sticker with the serialnumber ... if you can borrow a disc from someone ... that should work