Can’t install HP USB/Network Printer from Virtual PC 2007 due to lack of a USB port. This should not be a limitation since the printer is network-accessible but the print driver setup program complains and won’t let you finish the install.
When the installer complains about lack of USB port, simply click on the “Cancel” button while holding down the Ctrl and Shift keys. This will “magically” bypass the USB port requirement and allow the installer to continue. Be sure to have the IP Address of your printer handy as you will need that in a subsequent step to connect to your printer.
This may not work on all HP Network-capable printers, but I can confirm that it works for the OfficeJet 6310 All-in-one.
I found this solution on the HP Website