Pretty much the same thing happened to me as to the poster of this thread, jayray999.
I updated to win8.1 from win8. I had classic shell installed at the time.
As he said, "I noticed then that most Metro Apps were not launching at all. They would appear to launch then vanish."
After trying a number of different solutions, and using a microsoft troubleshooter that can be downloaded to repair apps, I was in the same boat. the Apps would open partway, and then minimize, where they could be seen in the taskbar. An attempt to restore them would bring them back for a couple of seconds, then they would minimize again.
Then I ran across this microsoft knowledge base article:
http://support.microsoft.com/kb/2798317The action that I needed to take was this:
"Make sure the All Applications Packages group has the Read permissions to the following registry paths:
HKEY_CLASSES_ROOT"
I found that the registry key had no permissions for this group. I changed the key so that read permissions were granted to the All Applications Packages group and bingo, the apps started to work.
Doing this repair does require having some experience in using the registry editor and also a knowledge of how to adjust permissions. If you are not used to doing either of these things, it would be helpful for you to have an experienced friend deal with this, as an accidental deletion of a registry key or incorrect permission setting can wreak havoc with your system.