This seems to be a popular problem in Windows 8 because the support forums are full of it: Without a reason Windows 8 store keeps hanging in the start screen and don’t finish loading. So here is a little workaround that worked for me:
- Rename the Cache folder to CacheOld at:
C:Users(Your User Account)AppDataLocalPackagesWinStore_cw5n1h2txyewyLocalState - Create an empty folder called Cache
- Run “WSreset.exe” as administrator
More infos and workarounds can be found here: http://windows.microsoft.com/en-us/windows-8/what-troubleshoot-problems-app