If you have the orginal software that came with your scaner and it says that it is compatible to Windows XP, you may need to use the disc to reinstall it. YOu will first need to turn off the scanner and unplug it from the PC. Then uninstall the old software from install/uninstall in your control panel. (start>control panel>install/uninstall programs, search the list for your scanner software.)
If you do not have the software or it is not for Windows XP:
There is the link to a site with a driver download specifically for your scanner, instructions on installing it for windows XP and also a link to answers to problems for your specific scanner.
Before you begin any download make sure your virus control software is up to date.
First click on the link "Instructions for XP installation and print it out.
Next click on a driver for XP from the chart to download it. When a window pops up click save and browse until you locate desktop. Save this file to your desktop. It will be an .exe file.
Turn off your scanner and unplug it from your PC and uninstall the oldsoftware as advised above.
Click on your new driver file to install it. Follow instructions.
Once the driver is installed, plug the scanner back into the computer and turn it on.
Restart your computer.
It should now recognize your scanner.
Try a scan.