The details on the touchpad will be in Control Panel>Device Manager in Vista or W7, Control panel>System>Hardware>Device Manager in XP.
Right click on the device, go to Properties and then click the Details tab. Scroll to HardwareIDs and take a note of the four characters which follow VEN for Vendor and also the four following DEV for Device.
Go to http/www.pcidatabase.com and input those characters in the two relevant boxes and follow the trail to the right driver. When you find the list of the Vendor's drivers, they aren't in order so use your browser's Find facility to track the Device details. With luck you'll have an executable file but some will be a zipped folder.
If you stlil want to know the model details, they are usually displayed in the Control Panel>System>General tab or if you restart and tap Escape and F1 together, the BIOS should show up and some detail might be in there.
go to command prompt...hit start>> type " cmd " in the search box>> then type in this command..." wmic bios get serialnumber " then hit enter,,,you should be able to see the serial number and look for drivers online.