As Arlene has stated, this has NOTHING to do with our anti-virus, browser, etc. Our FTM 2010 is NOT corrupted. When the "experts" at the help desk at FTM signed in with my ancestry account and tried to log into FTM 2010 they experienced the same problem - LOG IN FAILED.
This is something that needs to be fixed at the development end. Last November, when it happened, it took about 2 weeks but it was fixed. I was finally able to do everything normally in my FTM 2010 using my ancestry.com account after they changed something in their codes. This past week, for no reason, the same exact thing happened again - and I assume that it will (slowly) be fixed this time as well.