I have a stylistic lt c-500, assuming you have the same problem I ran into. There were 2 Unknown Devices. Both were part of the 82440mx Bridge. 1 of them is the "Fujitsu 3400 Pen", and the other is a Custom Driver called "Windows 2000 fujitsu driver" Which lets you use the sas.exe. This file, when place in your c:\winnt\ folder installs a tray icon which emulates Alt+Ctrl+Delete for you. After Installing the driver you need to manually copy sas.exe to WINNT and put a shortcut to it in your Start Menu. Ok, out of the 2 Unknow Devices the top one is usually the Fujitsu 2000 driver and the Bottom one is the Pen.

goto http://support.fujitsupc.com/CS/Portal/support.do

Select your Product, Series, Model and download Win2K's Pen driver and FPC Utility drivers.

Extract these file to say EX. c:\drivers\FPC and c:\drivers\Pen

Do Update Driver on the Bottom Unkown Device.

Do not let windows search for it, you need to use Install From A Specific List...

Then find "Other Devices" and hit next

Then "Have Disk" and browse to you c:\drivers\pen\ folder.
It will show Fujitsu 3400 Pen Driver.

Now do the same for the other unkown device except point it to c:\drivers\FPC.

You CAN manually add the FPC driver and just delete the Unknown Device. Doesn't really matter. I believe this driver was a quick fix for the Alt+Ctrl+Delete combo using its own API. It'll will work Either way.

When all done, you can find the sas.exe in the c:\drivers\FPC\ folder. There is also Instructions in there.
These same methods work on an XP Service Pack 2 install that I have Loaded. So far I have installed the Pen driver... Working on the FPC Utility Driver now. Wish me luck :book: