the same thing happened to me I decided to removed and reistall linux but I found that I caould not get back into widows after I had done this
so you are running xp boot from the cd and enter thr console recovery mode select the install you need to install and look through the commands there should be one call fix mbr
there is in 2k and I think its very similar.type fixmbr at the command prompt and confim you selections this should then allow you to boot into windows at least then you can check everything is there and then either delete the linux partitions and reinstall or attempt to repair it I am also a linux newbie
so there may be a linux based way but I know this works and will give you access to you windows partition.
I found this useful during my continuing migration away from widows to redhat 9.
Good luck hope this helps. :-)