System Restore, what does it do?

[OnionPatch]

Things just keep going wrong on my computer. First the sound stopped working. I checked every single thing but can't figure it out. It works when I play something through iTunes, but the system sounds won't work or any videos I try to play. If I check, it says there is no sound device on my computer! I think the driver is gone somehow but when I check there are five different sound drivers and all say they are working properly. Then it stopped recognizing my iPod when I plug it in to sync. Now on top of all that, it's running slow but my anti-virus can't find anything. Then, the other day, it just stopped working and I got a message that Windows shut down to prevent serious damage to my computer! :scared: Something is wrong.

I've been told I should do a system restore. I'm kinda scared to attempt that but if I do, what exactly does it do? Do I need to backup all my pictures, email and files? I'll have to go back to about four-five months ago, and I've had all sorts of installs and software since then. Will it be gone? I've never done this before. I guess this will be an all-day project? Is there anyplace that explains in simple terms how to do a system restore? Is it hard to do? Or is this a job for the tech-guy?

Thanks!