Re: why i dont install any app on my phone
If you are having a problem downloading Apps from the Store, you may have a sync error in your Microsoft Account.
Make sure the account can sync.
Settings > email + accounts > hold down on the account name > tap "sync" from the popup menu
If it will not sync, make sure the date and time are correct for where you are. Try removing any restrictions in Data Sense.
Check the account again to see if it syncs.
Try a Soft Rest - hold the Power + Volume Down buttons until the phone vibrates and reboots. You don't lose any data, but clear out system memory.