Why is my touch pad not scrolling using multi touch gestures?

1- If you reinstalled Drivers from the restore CD or Recovery Partition..It may be an out of date driver. In most cases these functions are brand specific and Microsoft Update does not provide them. In this case you may have to go right to the Samsung Support section of their site and see if there is an up to date driver.

2- It may for some odd reason, Turned that function off in the BOIS when you did the restore. I don't know how computer savvy you are, but you could look in the BOIS and see if the setting exists and enable it.

3- It's hard to say if it is the physical touch pad but it's rare if they wear out. If it was taken apart at one point, the ribbon cable may have not been seated properly and came out. Some have 2 small ribbon cables some have one. Kind of unlikely though if it worked before you restored it.

Hope this helps even a little bit...