I have seen several reports of frozen remotes and the only way that appears to work is to let it power down and then reconnect it - there is a mention of taking it apart and disconnecting but not something i would recommend - just power down. Also check which version of the software you are on and email XP with your problem.
V6 has 3 different version - Original , Big Button date stamp 8.3.22 and V06 date stamp 11.3.22 - when you get it back working look in Options, Info, and then press the top middle button corresponding to the arrow and this will show a date stamp