[Ham-Computers] Navigating DOS Screen Without a Mouse

[Jim Hill]

I'm using Terabyte Image for DOS to back up the C drive and 
encountered a problem.  I need to add an X to a box to indicate I 
want to validate during the backup.  Normally, I would use the mouse 
and left click the box, but as the name implies it's a DOS program 
and my USB mouse is inoperative.  I don't have a mouse port on this computer.

What keystrokes should I use?  I can easily reach the line that has 
the box, but can't click it. Incidentally, it's a nice program but 
it's too bad it does not have USB mouse support.

Thanks, Jim