my xbox worked fine. i went to work cam home and now when i put a cd in it came up with an error saying your xbox need service. it had a # 21 and the led was blinking red. it wont let me access the ms dash. please help me.

My friends did that not too long ago.... just restarting his xbox helped him....

What chip do you have installed?

If you have a Matrix check to see if it is still aligned
They have been known to move