If ‘Installation’ is greyed out then ensure that you are not recording or playing back a programme.
If the HDR-FOX-T2 is freezing before you can get to the correct menu then with the HDR-FOX-T2 powered down remove the aerial lead from the aerial in socket, and then have another go with the aerial still unconnected.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix dtt receivers.