Did you install any new software, add a new card, or run windows update the day before the freeze? Try removing any pcmcia cards and booting.
If not check your laptop's bios for any strangeness(missing ram and such). Many laptop manufactures have diagnostics tools, IBM is built into the system others may have a boot disc. Run the diagnostics and check for any errors.
If all failes you could try to repair the instalation if you have the Windows XP disc(not a system restore disc also take care not to format your file system in this process) . It's much like installing xp, but just before the partition screen (when it's detecting existing windows the second time) run the repair. *there are a few seprite repair features of the XP installer disc*
Windows should reinstall and not destroy the file system. Most programs should be fine, but there are some cases where you may need to reinstall a application.