I bought a new Antec IDE cable to replace my old faulty one. Now when i restart it doesnt. Then CPU fan seems to be working but the screen turns black . Would the new IDE cable be doing this.

It is not likely the IDE cable that you put in. It is more possible that you loosened another wire by mistake. I would look at your wires from your video card first. Remove them and put them back in to assure that they are in tight.

OK thanks i will try that. Ill get back to u if it works.