How do I fix a scratch on an LCD screen? Its not a small scratch. I can see a small white dot through it. Is it possible to fix? Is there a risk of radiation?

There is no risk of radiation through an LCD. Only blinding light that can give you a headache. (I tried using a CCFL as a desk lamp. Headache follows, and despite what people keep telling me, I don't think I look like was born at Chernobyl.) As for the scratch, you must first come to terms that your monitor will never again be perfect, and then decide what is the best course of action for yourself and your skills with the understanding that this will not be easy and it will take quite some time. Personally, this is what I would do. Use something to very carefully blot the bright spot, I would probably use a tiny bit of ink on the tip of a sharpened toothpick. (Apply at a bit of an angle parallel to the scratch to avoid pressure points and stray ink.) It is better to have small dark spot on the screen than a bright one. Next, turn off then unplug the monitor and lay it down as flat as possible. Then, with a very soft touch, clean the entire screen with a gentle sanitary wipe. No strong or abrasive cleaners. If t.p. is what you have than that is what you have. If the wipe is dry, put just enough water on it to make it just damp enough to clean the surface. Take a damp q-tip and dip it in some ash then brush off any rough particles. Gently rub the ashen q-tip along the scratch lengthwise using as little pressure as possible. Rubbing across the scratch may make things faster, but will make the blemish larger, trust me. Repeat with the ashen q-tip until you are satisfied that the edges of the scratch are no longer rough. Very carefully with a barely damp fresh wipe, remove the rubbing's from the screen. Here comes the hard part. What to use to help close the gap, and gloss the finish. Nothing that I have seen or tried is perfect. My fist choice would be to leave it and thank whoever you do or don't pray to that it still works. If this is not acceptable, then if possible, get or debo an anti-dust or anti-glare or privacy screen for the monitor. If this is not possible, but you have access to a water based clear acrylic pen with a satin finish, you could go with that. Do not use gloss or high gloss, shiny things attract attention. Whatever you use to cover the scratch, make sure it is water based, because the solvents in others will tarnish or melt the plastic overlay of the LCD. Another possibility is, if you know someone in the area who paints, perhaps you could get a little water based clear coat with a satin finish, and use a tiny bit of sponge to apply it to the screen. Using even a small brush will leave brush strokes, but if that is what you have, then that is what you have. Best of luck to you, I hope it works out. :)