Touchpad/Stick only works when external mouse connected

Hi, thanks for reading this cry for help.

     I'm a pc support guy for a big company, as are many of you out there.  This problem is one of those I can't seem to figure out.  Perhaps someone with an outside perspective can provide insight that I'm lacking at the moment.

Gear: Dell C800 Laptop.  Bios A21 (latest as of this post).  Windows XP Pro sp1 clean install after format, latest touchpad/stick driver.

Status: Touchpad/Stick has no response in windows until an external ps/2 mouse is plugged in.  Once the external ps/2 mouse is connected, the touchpad/stick begins to work fine in windows but shows up as a ps/2 device (nothing specific about an alps touchpad).  Strange side effect though, the external ps/2 mouse when connected does NOT work.  All it seems to do is enable the touchpad/stick of the laptop.

Equipment swapped: I've swapped out the plastics containing the touchpad/buttons as well as the keyboard.  There was no change in status at all.

Notes: After reading through these forum's I saw that some people had success when resetting the bios to defaults.  I see no setting in my bios to reset it to defaults, so I manually re-flashed the bios with the same version (A21) in the hopes that it will do what I needed.  After swapping out the touchpad/keyboard, the system did force me into the bios to set the clock etc.. so I'm asuming that means my bios got reset.

Dell diagnostics fails the mouse/stick no matter what.  With or without the external ps/2 mouse plugged in.

Troubleshooting 101 says that its not a hardware problem because with an external ps/2 mouse plugged in, it works in windows.  It also can't be a software problem as it fails both in a fresh windows install and in the dell diagnostics.  So, um.. a bios problem perhaps? I have the same bios on other C800's and they seem to be working fine.

Is it possible that something is messing with the IRQ and when I plug in an external ps/2 mouse it moves irq's arround to make it work?  If thats the case, I'm not sure what to do, I don't see any IRQ adjustments in the bios.

Message Edited by Blittz on 12-17-2003 05:38 PM