It's a long story but check Apple.com for reseting the PRAM. I will tell you how to update your mac:
1. Click on the
icon on the top left of the screen and press it.
2. A menu should appear and you should see software update, click on it.
3. A menu will appear and software update will be looking for updates. If it finds it, it will show up on the menu. Click
Install Updates and wait for the updates to install.
4. After installation is complete, the computer will restart (like after most updates and this is normal).
5. After the computer restarted and loaded into Mac OS X, go to
Macintosh HD, then go to
Applications and into
Utilities. In there you should see an application called
Disc Utility and click on it.
6. Click Repair Permissions and wait for it to repair. Once finished, then quit out of Disc Utility.
7. Check Apple.com for how to do firmware updates because some firmware updates use different updating technique than others.