|No, the chipsets are the same (at least I couldn't see any difference).This shows the specs for the A7V-VM which is the same as the A7V133-VM. (You can download the manual from the FTP site to check.) The northbridge and southbridge are the same. There was a site I found yesterday where someone posted that the chipsets were different but that apparently was in error.|
But as far as your particular problem, clearing the cmos should revert is back to the on-board graphics.
Unfortunately most Asus boards have no 'clear cmos' jumpers. They did however have the solder points where the jumper pins should be. Their position is marked on the motherboard. The Asus method is to short those 2 points with the end of a screwdriver to clear the cmos. You can try that or remove the battery--a couple hours to make sure.
When you bootup after the cmos has been cleared it will load default settings which will include the on-board graphics. Then go into cmos and set the date and time and any other settings for which default is not adequate for your particular system.