I also have autopilot problems with both 757 and 767. The AP simply dont work. It worked before, and when I got the 707 I used it for a while. But now I come back to use the 757 nothing works. Is there a known conflict between the 707 and the AP in the 757 and 767??

I did exactly as I usually do. Inserted the flight-plan, align IRS, TO runway, weights and balance, fuel, trim and so on. Now all of a sudden its no reaction. I engage the CMD and LNAV VNAV. They lite up like they are on but no engaging at all. Some times after TO, a few mins into the flight it suddenly goes ballistic, like the 757 all of a sudden think it is an extra300, trying aerobatic maneuvering.

I tried to look for answer, here and in the manual. But nothing.

I also reinstalled both planes three times. Uninstalling, removing the extra folders and installing again.