Here is a site that tells you what all the beep codes are.

http://www.pchell.com/hardware/beepcodes.shtml

as far as the colors on your monitor... I have come accross this before and have fixed it also... if you are good at soldering and are adventurous you may want to give this a try. The reason why your colors are going crazy until you hit it a good one is are loose connections in your monitor. The way to fix it in your case is this.

Please note... this is at your own risk... use caution.

1) unplug monitor from powersource and from computer.
2) turn on monitor to drain any power out of capacitors.
3) remove back of monitor case.
4) on the back of the tube there is a board that the tube is connected to. This is encased in a grounded metal shield.
Remove enough of the ground wires (most are soldered on) (do not cut them) to be able to remove this... you will have to heat up soder on the board itself where you see a large amount of solder so that you can remove it. Be careful and make sure that everything you take off or undo can be put back after.
5) once the guard is off and you can see the board clearly... you will notice that at the center of the board there are pins that are arranged in a circle... these are the ones where your poor connection likely is due to old solder. Re-Solder all of the connections.
6) put it back together and try it out.
7) if you have done a good job and nothing else is wrong with the monitor your colors should be much better.