I installed current Debian on a home assembled computer with a Gigabyte mother board and nvidia GEFORCE 9800 GT graphics card (no doubt the source of my problem, I think). In order to load the nvidia driver xwindow has to be stopped. However, in command line the computer repeats the message: Thus, I can't type anything because as I type the screen blinks and the error message gets inserted into whatever I'm typing = LINUX USERS SECOND WORST NIGHTMARE!
How do I run the driver under these circumstances?

I think it will understand what have you written?
To test yourself, Try to execute some other commands and if they are being executed successfully although auto inserted text is there, it means system will understand your command.

Even if the screen gets disrupted with the output, the input you type into the terminal will not be disrupted. Just type ahead as you would without interruption. Alternatively, use Alt+F2 to switch to a different virtual terminal and launch your commands there.

The blinking screen and constant error messages were either messing me up or interfering. After stopping xwindows an alt-f2 still got blinking+error messages. Finally I used vi with script name "a" to write the shortest script in the world: one line with the sh <filename> and chmod to make it execuatable. RESULT:
No more blinking screen and it looks nice in GNOME 2 but GNOME 3 will no longer run. It's absurd! GNOME 3 with screen blinking or GNOME 2 with NVIDIA drivers? Go figure.
@TobiSGD: should I start a different thread to try and solve the Gnome 2/3 issue?

As TobiSGD said, the output won't interfere with what you're typing. It might look like it is, but it's not. Just type like normal and hit enter, it will run what you typed, not what you see on the screen.

I think that is a good idea.