I have seen a couple of topics on this site around this but basically
copy the two usb driver files from the zip file into some convenient location
c:\windows\system or c:\winnt\system32 or whatever even c:\gp32 would do.
place the SMC and batteries into your GP32. Connect Gp32 to the PC usingthe supplied USB cable.
The PC should detect a new device. select have disk or similar on find drivers screen. Browse to location of the USB dirvers you downloaded, select the GP32USB.inf file and let it roll.
If the detected new hardware does not come up when you connect the GP32 either the USB port and cable and Gp32 aren't connected properly or you could have a device that is locking up the USB hub, Printers often do this, make sure the printer is turn on.
If this all still fails enter control panel, select add new hardware, select USB device, choose have disk or similar and again browse to the GP32USB.inf file and that should work. If you still have troubles after this write another response saying what you have done step by step and if I can't help I am sure some other kind soul on here will be able to
Cheers
MrT