clear screen & remove EA

[Forex Trader]

Hi,
Could anybody advise me of how to (via program script):
1. clear the chart screen because of comment
2. changing color in comment, so if i write comment("hello"), the color of "hello" is blue or red or anycolor or even blink, font size, bold, etc
3. remove program running in EA automatically when user quit by pressing certain keys.

Thanks for your help
suheimi