Windows has an excellent feature called System Restore. It backs up system files before every new installation so you can get the system back to it's previous state if you don't like what an application did to your system. Mac doesn't have this. But there are other options.
OS X 10.6, Snow Leopard, automatically archives old data and apps and reinstalls system files. This will solve many problems, and maybe generate a few. On OS X 10.5 and before you had "Archive and Install" which does the same thing. You will need:
One would think that such an apparently simple operation as recovering deleted files on your Mac hard drive would be implemented into OSX. However, not only that it's not, but there's no free solution to do this. Developers charge money for every kind of miscellaneous utility for Mac you can imagine, so this subject isn't different.
The battery won't charge. This is what happened to me a few weeks ago, and there's a whole set of issues that you might be experiencing.
First, your charger might be dead. If you have an older version without magnet attachment of plugin, the cable might be broken. If you have a newer version, your kid might have chewed on connector. This kills the charger as it produces a shortcut. Its incredible how much these chargers cost in europe ... Unless you're an electronics guru, its much better to buy a new one instead of trying to fix it.
I've spent numerous hours fixing the supposedly perfect Macbook and it's OSX. I guess I wasn't the first nor the last, so here's my experience. Hopefully you will save a couple of hours of your life by using my solutions.