It has nothing to do with adding the extras. That is just a coincidence. It
has to do with turning off your PC. Upon reboot it is not using the old
graphics card driver and is reverting to a vesa driver. I am not sure why
this is happening. It likely has something to do with the boot process.

The blacking out likely has to do with two things. The first is when you
change drivers and the second is likely just a delay while the monitor warms
up. Is it CRT or LCD?