I have 2 of these LG monitors in which there is a white 1 inch bar about 2 inches from the left corner & additional black bar to the right of this (nearly centre of the screen.I have replaced almost all capacitors of each of the supplies & some of the bigger capacitors on the Video input board but wih no change.The Original problem was blown H O/p transistor C5445.
I would appreciate any tips.
Thanks.

Well, I can't see exactly what the faulty picture looks like, but I think you've discribed it reasonable well, I get the impression that they are not clearly defined lines but blurry black verticul lines. I've seen this before, have a good look at the video section, usally the CRT Drive Board, and check some of the small value caps, look for any small value bi-polar caps near the Video O/P transistors, don't bother taking measurements, they will mostly measure OK, just change them all.
It could also be an earthing probleming, so check ALL earth leads, make sure the CRT is earthed.

Find below a screen shot of the monitor when it is first powered on ,the problem gradually disappears about an hour after it's first powered on.

Sorry guys couldn't paste an image into this.someone tell me how to paste an image here.

I believe the only way on this forum is to have your photo on the Net somewhere, and have a link to it from your post

You may find it easier to find this faulty component with a hairdryer and freezer spray. Heat the video pcb until the fault 'gets better' or goes away then blast the small value caps till the fault re-appears. Change that cap and the corresponding ones for the other two guns and it should be fine.
The three electrolytic capacitors connected to the output of the video process IC cause problems.