Need help trouble shooting on how to fix my MacBook Pro so it will start

Question

Ok, this is going to be a bit of a long one, cuz there are a good amount of details that go into the problem and how I have tried to fix it.
To start, late last summer I got my Macbook Pro 15" with high resolution anti-glare, 500 GB X 7200 RPM hard drive, and everythin else standard.
Next part of the story is that i decided to upgrade from my 3-year-old iPhone 3GS. So I preordered an iPhone 5 (never doing that again), and finally received it 10/05/12.
Wanting to synch my new iPhone 5 ASAP so I could fully play with it, I finally synched my old iPhone 3GS with my MacBook Pro for the first time. I had not previously synched it with my MacBook Pro, because all of the songs and stuff that were on it were from being synched with my family's desktop (from maybe a year or so ago; I don't synch my phones often.). I also had been lazy this whole time in not transferring the songs and stuff from the desktop to my MacBook Pro, so thats why I didn't synch my 3GS, because I didn't want to lose that stuff on my phone until I had made time to transfer the data. Because of this, I didn't use iTunes that much and I updated it only 2 or 3 times over the year that I had if before I got my iPhone 5.
After synching my old phone, I then tried synching the i5, but an iTunes pop up said that I needed to update to iTunes 7.0 in order to synch the new phone.
So I canceled the pop-up, and checked the updates in iTunes, and selected update (I can't remember what it said I was updating to, but I don't think it was 7.0).
After it started updating, it asked if I wanted to update something something else (I think it was an iOS update or something thing like that.).
I select update, because it looks legit, and why not update the whole computer when I'm taking the time to update iTunes? So the 15-20 minute installation estimation time turns into 2 hours (I think that it said that there was 2GB of update, but not sure.).
At that time, I think of how I don't remember if the update was 7.0 or not (maybe 6.9 or something like that was my thought.). So I tried to re-synched my i5 to make the pop up for iTunes 7.0 to come up. It came up, and I clicked the link to take me to Apple's site. I clicked the update to iTunes 7.0, and it started downloading from the internet, and it gave some download estimation time. Remember that the other iTunes and iOS thing was still updating while iTunes 7.0 was downloading. The problem was that I had to go to work a few minutes before the download of the iTunes 7.0 from Apple's site would complete and 1.5 hours before the other updates would finish. So I just left my MacBook Pro open, running, and updating/downloading.
After work, I checked my laptop, and it said something about finalizing the installation. So I hit that button to finalize or whatever it said, and it starts finalizing.
After waiting 10 or so minutes I check my MacBook Pro again, and it says that it needs to restart to complete the process. So I hit the restart button on the pop up.
It restarted, and against a blue screen there was a grey pop up that said that there was some error or something like that in the installation and that I needed to restart the computer again. There was only one button on the pop up, and it was the "Restart" button. So I pressed it, and it restarted again.
However, it didn't fully boot up (and to this day still doesn't) and get past the grey screen with the apple and the spinning gear thingy underneath it.
After like 20 minutes, I did a forced shut off, and rebooted while holding the option button to see if I could start my Windows side, since I have my computer bootcamped, though I haven't used Windows on it yet. The three options appeared: Windows something, Macintosh something, and Recovery HD. I clicked the Windows button, and after loading and stuff, Windows was running and working. So I'm pretty sure that my problem isn't a hardware problem, but a software problem.
So I asked a friend who is studying to be some kind of computer guy, and he suggested that I put in the Mac iOS X disk that I got with my MacBook Pro when I start up and try to get to Disk Utility. I did that, and was able to get to Disk Utility. And as he instructed, I (on the First Aid tab, I think) pressed "Verify Disk". He said that it started to look for problems and stuff. Then when it was done, I pressed the "Repair Disk", and he said it started fixing those problems. After it was done, I performed another forced shut off. I then turned my MacBook Pro on with crossed fingers, but it was still stuck on the gray screen with the apple and the gear.
He then suggested that we try to start it in Safe Mode, so we researched how to do it on my family's desktop. I tried holding Shift after the turn on tone and releasing it when the spinning gear appeared, but that didn't work. I'm still not sure if that's the right way to start in safe mode.
So right now I don't have any other ideas, besides spending money to get it fixed, which I don't want to do, cuz I'm not rich and I work hard for all these fancy toys.
It ***** to have the joy of getting the newest iPhone overshadowed by my MacBook Pro not working.
Someone, please help!!!

Answer 1

First off your older OS X boot disks are no good as you upgraded OS X to a later version.
When you held the option key down at boot, this entered Startup Manager and by what your describing you have Recovery HD, Macintosh HD (your OS X boot partition), and Windows BootCamp partition.
To repair the drive, you enter Recovery HD and use Disk Utiltiy there to repair the Macintish HD partition.
You also use Recovery HD to reinstall OS X 10.7 or 10.8 from Apple's servers, this should fix your problems without deleting your programs or files. (some third party with at boot kernel extension ones will have to be reinstalled)
All you need to know is here
Step by Step to fix your Mac
https://discussions.apple.com/community/notebooks/macbook_pro?view=documents