Quote Originally Posted by TheMaritimeMan View Post
I just noticed something really interesting. When I type commands in IBM PC BASIC, and the computer obviously injects erroneous characters in them, the commands won't execute - it throws a syntax error. So it seems like the characters are not just passively appearing - the computer actually sees them and tries to execute them.

For example, if I type "run", it changes to "ruj" and it won't execute. If I type "cls", it changes to "cls $", and the cls command actually executes, and then it throws a syntax error, as if it's due to the dollar sign being there afterward.

Does this still seem like something that just a video card problem would cause? It's not the keyboard because if I boot with the keyboard disconnected it still outputs bad characters during the memory count.
Entirely possible that BASIC reads back the screen contents. Wouldn't surprise me one bit.