I have a new Dell Studio running Windows 7 and have the same problem. I finally ran across something that explains the issue, for me anyway.

The Dell Synaptic Driver v13.2.2.2 seems to includes the following touchpad "feature":

three-finger quick launch (holding three fingers down on the touchpad for 1 second opens notepad!!!!)

I have been searching online all day for this explanation. I hope this helps you too.

Brett M,
Windows Outreach Team