Question : Keyboard Not Working - Again...

I thought this problem was solved but it re-emerged:  This duplicates and then adds additional information to question asked earlier.

Recently our office computer (Dell running XP) became infected with a multiplicity of viruses. We installed and ran a number of malware and spyware softeware packages which cleaned up the initial problem but our usb keyboard does not work most of the time (either wired or wireless). (We have tried different keyboards, ports, etc.).  Error Code 38 is in the device manager that another instance of this is in memory.

I''ve tried uninstalling the keyboard driver and it repeatedly shows conflict between our two HID keyboard devices and then keyboard does not work.  I did per a troubleshooting site onliine edit the UPPER filters of:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\4D36E96B-E325-11CE-BFC1-08002BE10318 and removed the PCTCore line just leaving "kbdclass" and looked for other instances of this and did not find any.  I also deleted the kbdclass.sys from the Windows directory.  I also turned off the Power save options on this computer.  

Things worked for awhile, even after many reboots and I thought everything was okay but I heard by phone today that keyboard not working again with same error code. Baffling.

Answer : Keyboard Not Working - Again...

I'd do a reinstall of the most recent service pack for the OS.

Then, in the device manager, go to View -> Show hidden devices (enable).

Now see if there are hidden entries for the keyboard, or any keyboards, and remove them all.