I deleted my mac partition HELP PLEASE!

Hello all,
So yesterday my mac was running really slow and so I thought " Hey I never use the windows partition ill just delete it and maybe it will make my macbook pro go faster" So I went to system pref and went somewhere or something where it showed the partition and there was one I was able to mess around with so I thought that must be it cause there was no way mac would let me delete the partition I was on. Anyways So I clicked some things like change or erase or something and went on my way. about 20 hours later after work and all I went to turn my computer on as it was turned off completely ( not sleep ) and it comes up with the white screen which is COMPLETELY white and then it about two mins later it shows a black screen with the words "Non-system disk. Press any key to reboot" which makes me think its trying to boot into windows which I never got to work anyways. So my question here is HOW DO I GET MY MAC PARTITION BACK?!?! I dont understand how it got deleted while I was on it. PLease help! I DO NOT have any disks what so ever. I feel like I am pretty well screwed. Thanks in advance!

Your post was moved here as it does not belong in Schweb's Lounge. Please read our forum descriptions before posting.

Now to answer your post......

First of all, you didn't remove your OS X partition as the system will not allow it unless you were booted off your install DVD and ran Disk Utility direct from the DVD.

Reboot your machine but this time hold down your OPTION key as soon as you hear the chime. You should get an icon showing your MacIntosh HD. Select it and press enter. Once you're booted into OS X, go into System Preferences, Startup Disk, and make your MacIntosh HD the default.

We'll deal with getting rid of the Windows partition later. Post back and let us know the result.