Unable to boot up in MAC 10.6 anymore

Question

Hey guys, 1 week after installing Windows 7 Home Premium, I tried to boot up in MAC OS but there was a problem. One thing to note is that during this 1 week, I have been able to boot up in MAC successfully.
After turning on the computer(My startup disk is always mac by default), I get an apple logo with a loading icon. An example would be this link
http://img225.imageshack.us/img225/1166/ipodspinxx3.gif
Will there be anyone who is able to assist me on this?

Answer 1

Have you tried pressing the OPTION key as it restarts?
It boots into manual mode this way, it should show any start up disks you have on your computer.
If you start up using the SHIFT key it boots into SAFE mode. Minimum extensions and stuff.
Here's the HELP menu search results (on the computer) for starting up:
Shortcuts for starting up:
Use these shortcuts when you start up your computer. Unless otherwise specified, hold down the specified key immediately after you hear the startup tone (while the screen is still black).
ACTION:
SHORTCUT:
Prevent automatic login
When you see the progress indicator (looks like a spinning gear), hold down the left Shift key.
Prevent login items and Finder windows from opening when you log in
After clicking the Log In button in the login window, hold down the Shift key.
Start up from a CD or DVD
C
Start up from the default NetBoot disk image
N
Start up in target disk mode
T
Select a startup disk
Option
To open the optical drive when choosing a startup disk, press Command (⌘)-period (.).
Eject removable discs
Hold down the mouse button.
Reset parameter RAM
Command (⌘)-Option-P-R
Show detailed status messages (verbose mode)
Command (⌘)-V
Start up in single user mode
Command (⌘)-S
Start up in Safe Mode (only essential Mac OS X items are started; some features and applications might not work correctly.)
Immediately after you hear the startup tone, hold down the Shift key. Release the Shift key when you see the progress indicator (looks like a spinning gear).