I had to replace my hard drive in my N5010, I got Windows 7 reloaded and working but I cannot get my touchpad to work, I reloaded the driver from driver download suppport. I always had a problem with 'run away scroll'.
The touchpad should work fine without Dell driver - they give you "only" additional functionality like turning touchpad on/off,sensitivity etc....
Press function key "F2" at powerup.this will take you to the BIOS screen.Try moving the cursor .If it doesn't work you might have a problem with the mainboard,touchpad or the cable that connects it to the mainboard.
For a more intensive test you can run Dell Diagnostics -press "F12" at powerup.If this option is not available you can also use Dell Driver and Utility disc:Insert the disc,reboot,press F12,boot from CDrom....
to confuse you a little more download Dell "DSC"
It's a nice and handy Diagnostic Tool running under Windows
Note: DSC only supports the following models: