Funny story really.... I had to go through all the hassle of trying to post on others threads for their response but it seems that they are only trying to get you to download their software, so here is the story and a way to fix your computer for the common layman when it comes to computers. Unfortunately, I am also a layman, but it seems that I figured this one out, so I am going to call myself a superhero for the good of mankind. So here is the way to solve the issue. Both Adobe and Microsoft should pay me a royalty for solving their computer issues. Anyways here goes.
OK, so I am a computer neophyte in the grand scheme of things but two things ended up being successful for me.
Since I go to school online I have books that are only in PDF format. A real crapshoot when you have error 0x80070091 going on because it only seems to effect Adobe.
I did two things. Although the file is not capable of being deleted, the file can be renamed (since it is empty anyone it does not matter), so rename that adobe file anything you want. I named mine hg. if you look, those keys are right next to each other and could have typed asdf just as easily. Anyways, the file name is irrelevant. What occured is that file is now moved out of the way to allow a new adobe installation to take place. I downloaded Adobe 9 and it is working perfectly. Hope I don't need system restore because that still does not work, but at least I am moving forward and being able to use the program.
The more appropriate solution if you are not in a hurry, is to use the Windows boot disk. That will allow you to run chkdsk on the system before windows starts running. That means it fixes the files and we are good to go again. Then you also do not need to restart save all your work again.
Hope that helps. It worked for me... Just compiled all the data points from these messages and got me back on my feet. Thought I would just write a concise email that hopefully will help everyone.
See. simple. Have fun. Write if you found this interesting or useful.