Same problem. HP laptop 6570b, win7 64 bit, printer HP Laser Jet M1120n MFP.
Plug & Play driver instal doesn't work - it can not find appropriate drivers.
If I try to install newest HP driver for 64 bit win7 (from HP site), it stops during instalation ("windows will stop program because of trouble").
If I try to install 32 bit driver version from HP site, it let me to the HP install window. By clicking "Install" button it stops saying "The installation program is not supported on this OS..."
What to do next?