Haywire: keyboard and touchpad mouse on Acer Travelmate 433

A few months ago, immediately after the warranty expired, the internal keyboard and touchpad mouse went on the fritz. The rest of the computer works okay. Symptoms:

- Works just fine if I plug in a USB keyboard and mouse.

- Internal keyboard produces a bit of random garbage when I use it, then stops working entirely. When I return to the external keyboard, the SHIFT key is permanently activated.

- Touchpad produces some movement on the cursor, then stops. External mouse now still operates, but the mouse button selects a lot more on the active window/desktop than I ask for, and I cannot unselect.

- Neither device produces a response at all from Mandrake 10.0 or before I load Windows (e.g. "hit F2 for BIOS setup" or LILO).

I unplug and reattach the external keyboard and mouse to no effect.

I've removed the keyboard and reseated the keyboard connector, which was a little loose. Only effect is that it went from zero response to garbage response under Windows.

One other strange thing I noticed. When I reboot from Mandrake, the screen often takes a while to display anything at all. Don't know whether it is related to the other problems.

Any advice? I plan to borrow another laptop soon as I can to try switching the keyboard.

Thanks for your assistance.

Update:

I've cleaned the contacts on the keyboard ribbon and reattached. No change in behavior.

Before that, I noted that the touchpad now causes no harm when I use it. The middle doesn't provide response, but the edges move the cursor. And both buttons work.

I'd like to believe that I can simply replace the keyboard and touchpad, but it seems kind of suspicious to me that they both went nuts at the same time -- like it's something more internal.

That said, is it a difficult/expensive operation to replace a touchpad? I know that I can find and replace a keyboard.