USB modem asks for drivers

hi guys,

i have a vodafone k4511 usb modem that detects and installs on a windows 7 / xp machine
but the machine i need it on asks for the drivers
it detects starts to install and then asks for drivers...which should install automatically, as you know.
i have uninstalled and reinstalled the usb drivers, but it still does the same
vodafone support is about as useful as a sledgehammer to the head, with support telling me there is a problem with the computer...duh! no kidding...so i turn to you guys

what else can i try?
will cleaning the registry help any info appreciated...

PK