Thank you Bob and Emill for your comments!
I had my laptop completely turned off for a few days now and the screen is still very dark, so that didn't work. I'll have to try other things.
It's possible to replace the backlight. It's just going to be a pain to replace it -- ie Replacing vs. cost.
If you only use it for Windows Movie Maker, I'd do the external monitor thing. And keep it off the internet. XP is out of date. If it's not online and still does what you want, it's fine.
So you can connect any laptop to an external monitor? Do I connect it with a scart connector (or cable)? I see something in the back that looks like the scart thing could go there.
hhmmnnn.......
It can be the laptop screen or the video card.
I would suggest you first check any adjustments available in the keyboard for brightness and contrast. Try putting the brightness to full.
Occasionally there is a graphics card icon in the toolbar which you can access. Click on it and check the brightness levels.
There might also be a VGA connector in your laptop where you can use to connect to another screen or external screen. Try this and if it turns out okay, your laptop screen is kaput!! Or if still no image then there might be a video card problem.
You can try updating or reinstalling the video card drivers by accessing the device manager. Or reinstalling the video card program itself.
Frankly if you feel the above suggestions are too complicated ... try to get some help from someone with intermediate knowledge of laptops. Consider this a learning experience! good luck !! 
Thank you Emill!

Yes I was trying to find where I could adjust brightness on the keyboard and on the computer settings... but couldn't find anything... and I'm sure it has to be somewhere!
Wow you know a lot about computers!! (My dad doesn't even know how to turn the computer on

) I will try that with an external screen, I think I see where that connector could be...
We could call a computer guy but last year he already said that that laptop was so old that it's not worth repairing (and there wasn't anything really wrong with it yet, just a few keys missing -my bird likes to work on the computer too whenever he gets a chance!

and it's not working very fast of course with all the things on it, but the computer guy who was repairing our computers before just cleaned the computer and deleted some things and it would get much faster again and have a lot more free space on it, but the new coputer guy didn't really do anything like that).
Well I will sure try everything I can.

Thank you again for your advice!!!
