Hello. Do you know what version of OS X you have installed on your MacBook?
If you have 10.7 (Lion) or 10.8 (Mountain Lion), you can boot your computer to a special recovery partition and try repairing your system folder. The flashing question mark means your Mac can't find a bootable system folder.
The way we can find out if you have 10.7 or later, is to reboot your Mac and immediately hold down the OPTION key.
Sorry for the delay. Rebooting with the Option key just took you back to the flashing "?".
If that's the case, then your Mac is running something prior to 10.7. That means we'll need to boot your Mac from your recovery CD, the one that came with your computer. We're not going to go through a recovery, but that disc is bootable, and contains Disk Utility, which is what we'll use to attempt to repair your system folder.
If you don't have your recovery cd, do you maybe have another Mac computer and a firewire cable?
Ok. There's one other option. Let's try booting into Safe Mode. This is a special type of startup, which checks the hard drive, and also boots with only a core set of software. To boot in Safe Mode, restart your Mac and immediately hold down the SHIFT key. Safe Mode startups take longer than a normal startup, due to the hard drive check.
Ok. That means either that your Mac is unable to boot into Safe Mode, or that perhaps you didn't press the Shift key soon enough. If it doesn't work after a second attempt, then I'm afraid we're out of options. You'll need to find a recovery CD from which to boot, or another Mac from which to boot, before we can check your hard drive.
I'll leave this ticket open. It will stay open for 2 or 3 days. If I don't see an update from you by then, I'll add to the ticket in an effort to keep it open. If you reply to this session, I'll receive an email notification, so even if I'm not logged into JustAnswer, I'll see your update.
Ok. Just reply here if you find the cd, or can borrow one from a friend, and I'll try to get back into chat and help you out further.