My Mac laptop computer is really messed up. I can't get it to totally turn on.

Try booting from the original DVD (holding down the C) and then use the Utilities (not the installer) to verify and repair your disk and permissions.

What he said. The question mark indicates that you don’t have a bootable OS, so you might want to try reinstalling. If you have files on there that aren’t backed up elsewhere, do this first: <http://docs.info.apple.com/article.html?artnum=58583>. An Apple store will likely let you borrow a second computer for the purpose.

Before you do anything, is your computer covered by AppleCare? If you bought it within a year, then simply call AppleCare or visit your local Apple Store. They will perform fixes or repairs for free, up to and above replacing the entire computer if they need to.

You can call AppleCare in the US on: 1–800-275–2273

You can call AppleCare in Canada on: 1–800-263–3394

You can call AppleCare in the UK on: 0870 876 0753

These are local rate numbers. If you are not from an above country, visit http://www.apple.com/support/contact/ and use the drop down selector labelled “select country or language” and choose your region.

Good luck. If you are not covered by AppleCare, the symptom you describe indicates that either an operating system is not installed or is damaged, and it is often best to simply do a reinstall using the system discs provided with your Mac.

While selecting the location to install Mac OS X, click on the ‘Options’ button (may be labelled as ‘Advanced’ in other versions of OS X) and choose the option for ‘Archive and Install’. This will place the contents of your current hard drive into a folder in the root of your hard disc entitled “Previous System”. If your data is unimportant, you can ignore the archive and install step, and simply click through the dialogs to install OS X directly (and wiping your hard drive in the process).

To begin the installation process, insert the disc and hold down the ‘C’ key on your keyboard. It is relatively simple to do, but I would still advise you to contact AppleCare or visit an Apple Store if your system is less than one year old (or if you have bought extended AppleCare protection).

All the best,
Richard