[chenlc03]

I have a WinXP Pro system. I used to run ThreatFire on it but decided to uninstall it. Everything went smoothly but when I restarted my computer the keyboard stopped working (under XP, it worked before XP was loaded).

I tried F8/Safe mode/Last Known configuration but none worked.

Fortunately, I was able to use remote desktop to login.

I tried system restore but it could not proceed.

I looked at device manager and it reported code 39 (corrupted driver). I uninstalled the driver and rescanned for hardware. Same problem.

I copied kbdclass.sys and i8042prt.sys from another Xp computer to System32\drivers. Nothing changed.

Finally, I decided to do an XP repair install (big mistake!)
Everything went well but then it asked for product key to finalize installation and the keyboard was not working.

I contacted the custom service from PCtools and I was told to look for TFkbmon in the registry.

I have UBCD4win available so I was able to search the registry but did not find one. Furthermore, UpperFilters value looks correct. HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E96B-E325-11CE-BFC1-08002BE10318}:UpperFilters = "kbdclass"

I am running out of ideas. Since the keyboard works find under BIOS/Live CD but stops working once "Windows setup (repair install)" is loaded, I would guess the culprit is an old file not updated during the repair process, but I just could not pinpoint it. Is there any other thing I should try?

[Mega Tron]

Hello chenlc03!

I will try to help you troubleshoot this problem. Besides the keyboard not working you can access the computer and it boots up Ok?

And... What is your keyboards brand? What type,model ect...

[Elvandil]

Did you experience a power failure or anything? Is your CMOS battery good (date stays put)?

No matter, it may be worth a look to see if the BIOS has the legacy USB support enabled. It probably does since you said the kb works before XP loads, but worth a look.

The one thing you failed to mention--is it PS/2 or USB? Have you tried the other type?

[chenlc03]

Hi, Thanks all for help. It's a Dell PS/2 keyboard. I tried other keyboard and all worked under BIOS/DOS/Live CD but not under Windows. Previously I can access my computer through remote desktop but now I am stuck since I am in the middle of XP repair install and I can not type in the product key.

[Mega Tron]

You might want to get a USB keyboard and try that to see if it works and finish the XP installation.

[chenlc03]

I tried that. No luck.

[Mega Tron]

What about Windows On-Screen Keyboard?? If you can access Start and Programs during the installation then you are in luck

Start>Programs>Accessories>Accessibility>On-Screen Keyboard

[Elvandil]

When you used the UBCD, did you import the registry from your machine (just asking in case you were looking at the UBCD registry)?

Do you have any restore points? If so, you can use the UBCD to restore a previous copy of the registry.

[Elvandil]

If you get back into Windows, ever, make sure that kbdclass.sys and i8042prt.sys are in your system32\drivers folder and then merge the attached reg file to replace the service keys (just in case). Try rebooting.

[chenlc03]

@Mega Tron

Unfortunately, there is no soft keyboard during XP setup ( I know vista has one).

@Elvandil

I tried system restore before, but windows refused to let me go back.

I merged your reg file into the registry (I am sure it's my machine's) but I still could not type in the product key.

[Elvandil]

Are you still stuck at the product key page? If so, try starting PNP after you plug in your USB keyboard.

Press Shift+F8. Do you get a command prompt? If so, type:

net start PlugPlay

No guarantee it will work at this stage, but worth a try, even if you just are able to cancel the installation, though I'm not sure it's possible at that stage.

[Elvandil]

I don't understand where you are. How could you merge the reg file if you are at the product key page, or did you restart the installation? That reg key will only help with a running XP system, not an installation.

Is legacy USB turned on in the BIOS for the USB kb?

Is it possible that the PS/2 got unplugged while the machine was running? That is often enough to burn it out (or plugging it in).

Restore points also have a full registry backup that can be restored with the UBCD4Win if you have any.

[chenlc03]

@Elvandil,

Sorry I was not clear. I used UBCD4win to merge the kb.reg. And then I restart the computer and it wen on to finish the installation. Thus I was at product key page again.

[chenlc03]

@Elvandil,

Just want to add that I have restore points before the repair install and I tried it (using remote desktop) but was unsuccessful. Can I still use those restore points (assuming they are not affected by Windows installation)?

[Elvandil]

How could you merge the key with UBCD? It would automatically merge with the CD's registry and not with that on the host machine.

You need to merge it inside the running XP, or edit it so that it merges to a new, imported key address on UBCD. Or you could write the changes manually to the XP registry after importing it.

One of the early steps in the installation is to delete all the Windows system files and restore points, so they are probably all gone by the time you get to the product key.