1. Begin by going to run and type in regedit.
2. Under HKEY_LOCAL_MACHINE, navigate to Software\Synaptics\SynTPEnh.
3. If DisableIntPDFeature is not listed, you will need to add it. Create a New DWORD by clicking on Edit > New and then selecting DWORD(32 bit) Value. You can also right click and choose it from the list that pops up.
4. Rename it to DisableIntPDFeature and enter 33 in the textbox under Value data. Make sure Hexadecimal is checked. Click OK.
5. Open the Control Panel. Where it says Control Panel in the URL, type in Control Panel\All Control Panel Items.
6. Double Click on Mouse and Click the tab for Device Settings.
7. You should see a check box for "Disable internal pointing device when external USB pointing device is attached". Check this, click the apply button and close the window.
Instead of Navigating the Registry, you can open up notepad, copy and paste the following into it:
[HKEY_LOCAL_MACHINE\SOFTWARE\Synaptics\SynTPEnh]
"DisableIntPDFeature"=dword:00000033
Save the file as AutoDisableMousePad.reg perhaps in the my documents folder or on the desktop. Double click it. If User Account Control (UAC) requires you to give it permission to make changes, click YES.