Weird apple logo glitch macbook air

Click on the apple logo on the left top corner, select force quit and quit all programs. It will be ok.

it sounds that you have problem in the video card.

Don't worry, mine also overheats reallyeasily. Watch this 'YouTube clip for some hints on cooling it down. Good Luck
http://www.youtube.com/watch?v=jHxr50KYvds

perhaps just a glitch in the software....go to control panel and adjust briteness again....if it don't do the trick, then most likely your bulb has seen better days and needs replacing

did you install anything new or damage your comp?

It may be a possibility that the hard drive has gone bad or a connection to the hard drive. The spinning wheel and apple signify the kernel boot, or in other words, the process in which the machine finds the hd and os/software.. you need to bring your machine into an authorized repair center to have a system diagnosis to verify that no other parts of the machine are bad. That model is notorious for having bad hd's.

Your best bet is to reset the System Management Controller;

http://support.apple.com/kb/ht3964

...and then reset the Parameter RAM:

http://support.apple.com/kb/ht1379

If it persists after that, try Safe Mode:

http://support.apple.com/kb/ht1455

...if that persists, try booting to your install DVD and running Disk Utility:

http://support.apple.com/kb/ts1417

..also note in this article that if for some reason you are unable to boot into your Install DVD the instructions for using fsck will do the same thing.

If that fails to resolve the issue, you'll want to reinstall the system, but that is a bit more of a sticky wicket since you're on a Macbook Air that does not have an optical drive. You can use remote disc sharing with another Mac to do this:

http://support.apple.com/kb/ht1131

...and then boot to that shared disc:

http://support.apple.com/kb/HT2129

..and then reinstall:

http://support.apple.com/kb/ht1710.

If none of these steps resolve the issue, it will likely need repair at an Apple Authorized Service Provider or Apple Store.

that normally happend when the macbook do not find the software you can read this apple post http://support.apple.com/kb/TS1440

Press and hold the power button. After a few seconds, the MAcBook will shut down.
Regards,
Cybernanga

Unit has either had a logic board failure or a heatsink failure, most likely a logic board failure though.