This behavior can occur if a program installs a kernel-mode driver that attaches itself to the standard keyboard driver (I8042prt.sys) and does not support Plug and Play I/O request packets (IRPs). Examples of programs that exhibit this behavior include:
Pgpdisk version 6.02 and 6.5 (installs Pgpmemlock.sys and Pgpdisk.sys drivers)
Adobe Type Manager version 4.0 (installs the Atmhelpr.sys driver)
To resolve the behavior, contact the manufacturer of your program to inquire about the availability of an updated version of the program that is designed for use with Windows XP.
To work around this behavior, uninstall the program that causes this behavior, and then restart your computer.
The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.