I have been working on a Dell Latitude D630 (not under warranty) where the touchpad does not respond and/or has stopped working all together. We have swapped out touchpads from known working Latitude D630s and still no response. In addition, we have swapped out motherboards and still no response. I have ruled out all possible hardware issues and was wondering if anyone has an idea about what I should look into next. Any ideas on possible software issues?