Unable to find core driver

Hi, I hope someone out there can help.

I've recently got a new pc preloaded with Vista Home Premium, and it won't
install me Epson Photo Stylus RX420 properly. The scanner function works
fine, the printer as a whole works fine on a laptop installed with Home Basic.
In Device Manager, it is listed although has a ?mark in the icon. I've
tried using the Update Driver Software tab in the properties and always get
an Install Error message "Unable to find a core driver package that is
required by the printer driver package". I also get the core driver message
through Printers>Add Printer .
Windows Update recognises that there must be a problem, as it lists an
update that I'm reccomended to install. Problem is that fails as well giving
a message "Error found Code 80070BC8.

Anyone got any clues??? Thanks, Mark.