Ok, firstly the one red light problem is a HANA chip error that deals with the display and if you have this error then you can try turning your Xbox 360 off and back on again and hoping that sorts it out (it sometimes does!), although it is likely you will have to send it in to get it fixed.
Or you can use an Xbox 360 Repair guide to correct this error.
Second problem is the 2 red lights, and this is down to overheating.
There is a few things that you can do and to fix it you can lift up the power pack off the floor and put in on top of an open box so it can get more air.
Also get a fan for your Xbox 360 and make sure that this too is well ventilated and you should solve this one.
Give it a good dust also as this can be a major factor with this error.
Three red lights is the most common error and it is caused by the 2 main chips overheating and to fix this you will need to either repair it yourself or send it in as you need to find some way to stop the heat build up.
If you have the 4 red lights you are normally in luck! As this error is just the AV cable not plugged in and you just need to give it a push and it will work again normally.
I hope this article has given you a quick overview of the problems that you can get with your Xbox 360 and helped you figure out what is wrong with your console.