Got red flashing light on console of the xbox saying e 74

If this xbox has never been opened and is less then 3 years from the date of purchase, Microsoft WILL fix this for free for you.
However if its over 3 years or if its been opened for any other reasons then this may help, You need to have the motherboard fixed, do to this you need to take the xbox360 apart then reflow the board.
there is a great 6part video guide on YouTube to view for free. 6 videos from the same fellow, each video is a few mins long, and goes over everything for you.

http://www.youtube.com/user/ohiocitysales#p/u and its free unlike some eBook site.

I actually used the same method to fix over 450 Xbox360 units with no problems at all, barring a few (but i have done nearly 500 so you expect a few problems along the way), you just need a few things though like a heat gun and some thermal paste. sounds hard, but it's very easy once you start!

Hope this helps in some way.