Hi all, I have a previous post in this thread saying how I also can't view games. I found a way to get around this when this happens. When this happens:
1. Pull up the Task Manager
2. Go to the "Processes" tab
3. Find and end the following three processes:
a. League Of Legends.exe *32
b. LolClient.exe *32
c. LoLLauncher.exe *32
tip: if you sort by memory usage, they should be easy to find as they will be near the top, using the most memory
After you do this, everything related to the League of Legends game will have closed. Restart LoL by clicking on the icon, sign in, and you should be able to spectate again.
This has worked for me the past few times, hopefully it will work for you as well! Good luck!