My MBP will not startup properly! I have a Macbook Pro 2008 aluminum 15-inch that runs on OSX snow leopard. Whenever I turn on my laptop, it boots up (apple logo and spinning wheel appears), and then goes into a loop of blue screens. I think the problem has something to do with the login process, because I sometimes see mouse and the brightness and sound icons appear, but it always fades away.  

I tried doing  fsck (command s), but the same problem's there. Safe mode also doesn't seem to work, unless I do verbose mode, but then again, it loops after the apple logo (grey screen). The recovery mode (cmd r) doesn't work at all. I tried pressing the option key but all i see is one disk, and that one still leads to series of loops. I also tried running the disk utility from my bootable usb but I don't know how to boot it. I tried pressing c and also tried the doing the option key thing. They both don't work, the usb doesn't appear at all. I tried resetting my pRAM, that doesn't help either. HELP! I just know that something is wrong with the disk, but I cant fix it because I can't go to recovery mode.
Blue screen is indicating a user level problem loading your specific settings.

You can overcome this in two ways:


boot in safe mode and log in and make a new admin account - set that new account to auto-log in or disable auto log in.
boot in single user mode, run fsck as directed, then mount the filesystem and delete /var/db/.AppleSetupDone and type exit


At that point, you can let the setup assistant create a new temporary admin (and temp_admin might be a good user name to choose to avoid matching an existing user name) so you can look at the system logs and clean up whatever user preference or program is interrupting the boot cycle.

If as you mentioned, you really can't boot at all off that drive, then you have bigger problems and need to bring a new OS on an external drive (or perhaps SD card) to the mix or seek help from someone that can back up your files or assist in reinstalling the OS from an external source.