Have you installed the VCOM drivers?
Download and install the drivers from here [Only registered and activated users can see links Click here to register]
Try using PdaNet first.
Also try going through this thread [Only registered and activated users can see links Click here to register]
If the phone is still not recognized, uninstall the PdaNet drivers and try another set. Before installing a different set, uninstall your phone's device ids using [Only registered and activated users can see links Click here to register].
Never have more than one set of drivers installed.