Issue:
Steam - Error: This game is currently unavailable.

Solution:
1. logout of Steam. If you click on the systray there should be a settings option. Under settings should be a logout option.

2. Kill Cedega and Steam. (If you are running it)

3. delete ClientRegistry.blob in the Steam folder.

4. Start steam up again. You should get a downloading processes(this is good). Then it will ask you to login again and everything should be a-ok.

Maybe making a script to delete the ClientRegistry.blob at startup would make things less annoying?

Thanks to Falcon006