Hello, my name is Dan.
I will do my best to help you, the only stupid question is the unasked one.
This might fix it.
Select Force Quit from the Apple menu or press Option/Comand/esc, you will get this.
What is in the list depends on what is open, click on Finder and then Relaunch.
The next thing I recommend is repairing permissions, do this even if iPhoto starts working.
Repairing Permissions That PDF explains how and why.
It also would not hurt to do a pram reset (I recommend using an attached USB keyboard for this, wireless is very difficult for this).
A Windows keyboard will work fine, the Command key becomes Control, Option is Alt.
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.
This will also help, more than likely the file structure is a mess, this will help straighten it out.
This also works best using a USB keyboard.
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.
Please let me know the results.