INVALID SIM MY HT C's 4G WINDOWS Radar CANNOT RECOGNIZED MY SIM CARD

Your phone says "Invalid Sim" means that your phone is locked to particular Network.To solve this problem you need to get your phone unlocked.You can unlock your HTC Radar 4G phone from Network lock using unlock code.It is the best and safest way to unlock phone.You can get such codes from your Network service provider or any third party online vendors like TheUnlockSpot.com here you need to specify your country,Network name to which it is locked,IMEI number of your phone.Then they deliver unlock code to you through mail with unlocking instructions.Using this you can unlock your phone from Network lock easily.