Go to Start/Printers and Faxes/ Add Printer.
Click 'Select from List'
Scroll to R300 [ or any other R300 series machine in the list
You will now have the basic R series driver.
Also I note that you haver printer post st to
This is for old style parrallel printers - select instead the USB printer port.
See what happens.
However if Epson do not support R300 on Win 7
See if any of the other R300 series will[Now upto 365 and beyond]