Touchpad Mouse working erratically

I have an  Inspiron 8600. It recently had a trouble with the video card and I had to send it back to dell to fix it. Now that I have received the computer from dell, there is someting wrong with the touchpad. It works fine if I don't plug anything e.g. network cable, power cable etc. As soon as I plug anything, it starts to work very erratically. I plugged in another USB mouse which works fine but touchpad doesn't seem to work.

 

I tried to restore the system to an earlier date but it didn't work. I also tried to uninstall the driver and then reinstall it but that hasn't worked either. Please let me know, if anyone has any tips....