Hello, my name is Dan.
I will do my best to help you, the only stupid question is the unasked one.
Okay, this is what I want you to do.
Press and hold the power button down until the machine shuts off.
The second thing I wanted to do is reset the pram.
After the you reset the pram I wanted to do a safe boot. The instructions for both of these follow.
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.
You can actually go from the pram reset into the safe boot, as soon as the last chime happens press and hold the shift key. You have to do it immediately following the chime.
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.
Your machine should now operate normally. Let me know please.