Give us a little more information about the install of RedHat.
1. Is Windows XP on a NTFS partition or fat32?
2. Is RedHat installed in the same drive as XP? Or, do you have two physical drives on the system, one for XP and one foe RedHat?
3. Did you set up a partition ahead of time with a partitioning utility, such as PartitionMagic, or did you use RedHat's install partitioning utility during the install?
4/. Most importantly, did you defrag your XP partition(s) BEFORE installing RedHat?
5. Finally, what system is the install on? Is it a HP or Compaq system?