When you plug in the usb does your pc recognise your phone being attached?
Maybe your usb driver needs updating..... windows xp?
Unplug your phone from your PC, download the latest Samsung USB driver from
http://www.rootschat.com/links/0e1n/.
When you are ready, go to Windows device manager, search for the problem device (phone usb connection), right click and choose Update Driver.
> Choose "Browse my computer for driver software"
> From the browse screen navigate to "C:\Program Files (x86)\Samsung\Samsung PC Studio 3\USB Drivers" (for Winx64) or "C:\Program Files\Samsung\Samsung PC Studio 3\USB Drivers for Winx86".
>Click Next and your device drivers should be found, select and install.
> Restart PC, open pc studio and plug in phone.
Hope this helps.