From a newsgroup post: "To increase the keyboard buffer size, run regedit and go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Kbdclass\Parameters. Look for the "KeyboardDataQueueSize" DWORD [REG_DWORD] value in the right hand pane. Double-click on it, check the decimal box and double the value shown there (default is 100). Then, under the same registry key, find the "PollStatusIterations" DWORD value, and increase it from 1 (default) to 2 or 4, by performing the same steps above, until your keyboard no longer exhibits interruptions".
A comment on Philip Gauthierís comment, after following his steps my system ignored all PS/2 devices. Be cautious when modifying the registry.
You may get this error message if you unplugg the keyboard and the mouse.
Device: \Device\KeyboardPort0 - This event is usually generated by computers connected to a faulty KVM (Keyboard, Video, Mouse) switch. If no KVM switch is used and if the keyboard is behaving normally, no action is needed. To avoid this message, try increasing the value of ResendInterations in the Registry key Current Control Set\\Services\\i804prt\\parameters. Or, try using a different keyboard.
The symptoms given also often appear when using a USB keyboard, and pressing any of the Caps/Scroll/Num Lock keys. It can be ignored if the keyboard is working correctly, otherwise use solution given.
Device: PS/2 keyboard - Error founded in Windows XP computer management Event viewer system properties each time I was opening a new session. To resolve this error event:
1- Start Registry Editor (Regedt32.exe or Regedit.exe)
2- Go to the following sub key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\i8042prt\ParametersName: ResendIterations
Data: 0x00000000(3) (default)
Then modify the value to 0 instead of 3.
Device: <blank> - In my case, I was trying to install a HP printer. Every time I would reboot it would give me the "found new hardware wizard." The drivers were there but the printer was not shown on my system. I restored a recent backup of my system state and that has fixed the problem.