Did you get “Attention required. Press here” followed by a “ connect to a wifi network or your PC to complete the download”? 

Recently I’ve purchased a game from the Windows Phone 7 marketplace. After it was succesfully downloaded, I couldn’t find the game in my “Xbox Live Games” section of the phone.

When going back into the marketplace using my phone and searching for the game, selecting it and pressing “Check install”, I noticed the game was stuck at “100% downloaded”.

The solution:

1) Make sure you are connected to WiFi or via USB to your computer with Zune software
2) Press and hold the download indicator for the game or app (which is stuck at 100%) and a menu will appear which gives you a “Retry” option. Select retry and if you’re lucky – it will go OK this time.

Please leave a reply if this helped you!
Good luck!