Hello, my name is Dan.
I will do my best to help you, the only stupid question is the unasked one.
That is known as a kernel panic, the message can look like one of these below.
This is usually software but can be a hardware incompatibility such as failing or failed RAM.
Sometimes some maintenance dan fix it sometimes not.
I recommend a pram reset followed by a safe boot and repairing the permissions.
Pretty much in that order, it may or may not clear the problem up.
The thing to do after that is to reset the PMU or the power management unit, and cleaning the RAM contacts with a pencil eraser.
To do a PRAM reset, you need to restart your machine and hold down these 4 keys.
‘Option’, ‘Command (Cloverleaf or Apple)’, ‘R’ and 'P'.
Keep them down until you hear 4 startup chimes.
If you have a wireless keyboard then the procedure is a little bit different.
Use the very same keys but wait until the first chime and immediately press and hold those keys. I recommend getting your fingers ready because timing is critical.
This resets all of the system buses on your computer, USB, FireWire, display, ethernet and your keyboard/mouse/trackpad.
This will correct many faults but not necessarily yours.
To do a Safe Boot, restart and before the first chime press and hold the 'Shift' key.
Wait until you see the Apple logo and the spinning gear appear, then let go.
It can take as long as 20 minutes to load, so please be patient.
When the login screen appears it will say in red on the login window 'SafeBoot'.
Now login and give it a few more minutes to finish loading.
Try doing whatever it was it was giving you the problem. If it works then probably the problem is solved, so restart normally.
If the problem persists then restart normally also, other fixes will need to be done.
This PDF explains how to repair your permissions.
If those three do not do the trick them please let me know and we will move to more invasive techniques.