Pointer freezes after Win 7 update

Hello,

I have just installed Win 7 on my Vostro 1220.  All was fine until it started to update some drivers.  It updated one for the pointer (Alper or something), and now the pointer freezes on the screen everyr 3-4 seconds.  I have to press any key to unfreeze it.  This only applies to the touch pad: if I plug a mouse in via a USB port then that works fine.  Anyone else have this problem?