Rans6,
I am glad you seem to have this sorted.
At the end of the evening I went to shut down the machine in the usual way and it opened the shutting down options box (restart, change user, switch off etc) but I noticed that the text in the options box was corrupted, all of the letters were displayed as small rectangles. Not a problem, I know that the last click box is for switching the machine off so I clicked that and the machine switched off.
This morning I switched the machine on in the normal way, it booted up to the log in screen, I logged in and then it seemed to just stop with a totally black screen except for the mouse pointer white arrow. The usual desktop didn't appear. The machine is not dead, the mouse pointer still moves but it doesn't find anything to select (so I know it isn't just doing everything as black on black). Oh.
This sounds like the Fotoxx corrupted some of your system font files. FYI unlike windows linux can run in a number of different modes called run levels. Normally you will be running in run level 5 (graphical multi user). In this normal startup sequence the system will boot into a command line run level to load all the system components (usually hidden by a splash screen) and then at the end load the graphical display manager which runs the desktop. It sounds that this is part loading but possibly hanging because it cant access the corrupted font files.
From the Linux Mint installed drives the system boots normally up to the entry of user name and password, which it accepts, and then it progresses nearly to the desktop display, stalling with the mouse pointer working on an otherwise totally black screen. The system has not crashed. When the power button is pressed momentarily a small amount of text appears at the top of the screen prompting for login and showing the volume name on the hard disk and then it writes shutting down info and then the power supply switches off.
The small text is a run level 3 or 1 (ie command line) login screen, which it is falling back into to carry out the shut down sequence.
one of the advantages of linux is that it produces extensive easily available log files to tell you what it is doing. The exact location may vary, but a good place to start is:
/var/log
/var/log/boot.log might be a good place to start. General system messages are logged in:
var/log/messages
Depending on which display manager you are using it will have its own logs.
These should give you a clue as to what is happening. The other useful tool to use from a command prompt is dmesg. By executing the dmesg command, you can view the hardware that is detected during bootup process and it’s configuration details. There is lot of useful information displayed by dmesg. You might find it helpful for troubleshooting, when you encounter an issue.
WRT to video you might consider VLC player which should be available through your software package installer.
HTH
EG