Can't boot OSX, trying Ubuntu but can't run LiveCD or LiveUSB

So through a series of increasingly poor decisions, I unintentionally wiped a partition that appeared (while in Disk Utility) and am unable to boot my compter. At all. It was 200mb and had something like 49 hidden files, and since I'd never seen this partition before I decided to format it in hopes that it would just...disappear. Bad move.

In conversation with a friend, he believes I deleted the Partition Table...? and I can no longer boot into OSX. Upon restart I get a gray screen (no Apple Logo), then black screen with "Error loading operating system".

Next I tried creating a liveUSB and liveCD of Ubuntu in hopes of accessing my HD, removing all essential items, and then wiping the HD completely and installing Snow Leopard (currently on Leopard). Tried holding down "C", "Option", Shift + Option + CMD + Delete" (read on some forum) and nothing will let the computer read the files. I've checked on other PC's that the CD does actually contain the properly burned ISO and all.

Running on a 2007 Macbook with an upgraded 500gb HD. Don't have any other specs on it other than that...bit of a newb. Any help would be greatly appreciated as HD contains important files...obviously...haha.

I do not understand. You have got to boot from a live USB drive or a live CD?
If not, then what reason?

So through a series of increasingly poor decisions, I unintentionally wiped a partition that appeared (while in Disk Utility) and am unable to boot my compter. At all. It was 200mb and had something like 49 hidden files, and since I'd never seen this partition before I decided to format it in hopes that it would just...disappear. Bad move.

Click to expand...

What you nicely deleted was your EFI partition which effectively killed OS X. The solution is to reinstall OS X as you found out. Try resetting the PRAM/NVRAM first and then try rebooting with the Linux live CD again. If it doesn't work, try this procedure which is below here:

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Restore default bootloader without harming partitions

Fri, Nov 20 2009 at 7:30AM PST • Contributed by: tofergregg

If your bootloader gets changed or corrupted, this fix will restore it without damage to your disk partitions.

This hint may be a bit esoteric, but I thought I was up for a long night of reinstallation pain before stumbling upon this fix. I made the mistake of trying to use an Ubuntu 9.04 boot CD to install Ubuntu to an external (USB) drive on my Mac.

Don't do this, unless you know the following: Regardless of the fact that you chose the external drive upon which to install Ubuntu, you won't be able to boot back into your Mac without changing the bootloader. I ended up with the dreaded question mark folder when I tried to reboot my Mac, and nothing worked to boot into my OS X partition.

Luckily, I have a bootable external drive with OS X on it, and I was able to boot into it by holding down the Option key (the primary partition still did not show up).

I started searching online for the fix, and it seems that Ubuntu changes the Darwin (default) bootloader to Grub on your internal disk, and OS X won't use it (at least not by default). The fixes listed were kludgy, and amounted to either installing another third party bootloader (called "rEFIt") or completely wiping your internal drive and reinstalling OS X (even a standard install won't work).

Anyway, the fix turned out to be easy with Disk Utility (and probably possible from the OS X boot disc). Run Disk Utility and click on your internal hard disk (the disk itself, not the partition under it). Then click on the Partition tab. If you move the triangular slider that adjusts the partition up and then back to where it was, the "Apply" button becomes active (it starts greyed out). You can now click "Apply," and the partition will be left alone, but the bootloader will be recreated.

When I did this, a window popped up that said, "Are you sure you want to partition the disk? Partitioning this disk will change some of the partitions. No partitions will be erased." If you get a message that partitions will be erased, I'd look into it more before going ahead!

I was surprised that this worked, but when I rebooted, the computer booted straight into OS X from the internal drive.

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Note: You may actually have to use another machine via firewire for this to work for you. The only other option I can think of is remove the HDD, place it in an external carrier, try to extract what data you can using whatever means at your disposal. And then wipe the drive for a reinstall of OS X.

Regards.