That's part of your registry. Rather essential, as you see. http://support.microsoft.com/kb/307545 tells what to do.

Nice, isn't it, such a readily available and detailed instruction?

The only prerequisite: you need the Windows XP CD. Did your PC come laptop come with one? If not, your options are:
- do the same things as in that thread after booting from a Linux Live CD (other tools, other syntax)
- boot from the System Recovery media or partition (see Toshiba's user manual for the details) to bring the machine back to factory state

Kees