I have now tried about ten times to upgrade my 64bit Vista Ultimate to Win 7 64bit ultimate (retail version) without success. I get the error message every time at 86%. I have played with my RAM, went into msconfig and unchecked everything but Microsoft files, I have removed AVG free, removed all of my cd/dvd burning programs, tried two different dvd drives and even copied the files from the dvd to an 8GB compactFlash card. 86% and I get the error, every time. Even downloaded PerfectOptimizer which says it fixed a few registry errors but wants me to purchase and register to get the other 584 errors in the registry. Not sure what I should do next. I am tempted to purchase PerfectOptimizer and try it although I realize that only delays the next episode of frustration. I am open to suggestions, please....please.