Why don't you let me remove unused software?

I have around 10 different computers in a department that are being replaced. They run XP, Vista and Windows 7.

Since we have around 5 Dell printers, they all have the software installed. But now these computers are to be moved to a different department with a different purpose.

And not a single one of them is able to remove Dell software.

This is what happens (software varies, since there are different OS's and printers. But this is a good summary):

1) Click on the software and click uninstall:

2) Most uninstallers have some remaining software. In 2 computers, this window is blank. There's nothing to uninstall

3) Awesome! Removed, right!?

4) Not really...

This is happening in all computers with Dell printer software. If I'm able to remove the the drivers, the uninstaller itself never goes away.

I already emailed support on Monday, but didn't get an answer.

Does anyone have a suggestion?

Thanks,