ok, this is a simple thing:
1. unpack .cab using e.g. 7-zip to e.g. c:/printer_drv
2. click start>>faxes&printers and (remove the installed printer) add printer>>local on usb
3. click 'from disk' and browse prnhp001.inf file from c:/printer_drv and click OK
4. choose your printer (hp845c
) and click next...
5. Now You can handle, I guess
ps. sorry for my english