When you blue screen, if your system doesn't have a reset button, try
hitting Ctrl-Alt-Delete, if that doesn't work, try hitting that combination
twice and see if it gets the system to reboot or possibly bring up task
manager from which you can get to a menu that has "restart" and "shutdown"
on it.
Yes, it might have been useful to see the entire error message but the
message as you posted indicates a driver problem. Start with the scanner as
that is the most recent change. Indeed it does make sense. The fact you
purchase hardware new does not mean the drivers included with it are the
most recent so you must check the manufacturer's website for the latest
drivers. You have no idea how long the item was in the shelf in the store
or in a warehouse waiting to be delivered and in that time, updated drivers
might be introduced.
Also, have you checked it's compatibility:
http://www.microsoft.com/windowsxp/pro/howtobuy/upgrading/compat.asp
Further, if the scanner has a software bundle included with it, while the
scanner and the driver may be compatible, the software may and often does
cause conflicts that can cause the system to crash. And, even if the
scanner is XP compatible, you may have other devices with which the scanner
conflicts and that could be the issue. Is the scanner plugged directly into
USB port (I'm assuming it is a USB scanner) or is it plugged into a hub. If
plugged into a hub, are there other devices plugged into the same hub.
If plugged directly into the port on the PC, is the port in front or in back
of the PC? Also, is it a port that you added after or is it a port that was
built into the system when you purchased it? If you added the port, you may
have an IRQ conflict necessitating moving the card to another slot. Or, you
may have some other card, soundcard or some other such card that needs to be
moved as it might be conflicting with the device. Additionally, if your
other drivers are not up to date, they may conflict with the scanner and
cause the system to crash so you need to be sure those drivers are up to
date if we can't narrow this down. If the system blue screened when you
tried to run the compatibility wizard, there might be a corresponding error
in Event Viewer. Open Control Panel, open Administrative Tools, open Event
Viewer, look for errors that correspond to when the blue screen appeared and
double click the error, the information contained within may give a clue to
the source of the issue.