What does this mean ? What should I click please?

[ng4ever]

 

[upnorth]

Quote : " Click on Block if you did not connect a keyboard to this computer or do not recognize this USB device. "

 

[maniac2003]

When HMP.A detects a new keyboard device it gives this alert.
As @upnorth mentions. If you connected a new keyboard, or changed the port the keyboard was connected to, click allow otherwise click block.