Dear Murugan,

You will be getting strange answers if you ask for strange problems, but one will match the solution to your problem. Keep trying it.
I have a habit, may be others might not agree with. As everybody has I also came across strange problems, so I keep that PCB aside, and try to start working on another pcb if available or draw all the circuit on bread board. It takes time but solves the problem, and most important is that we should also know what the problem was.

Rauf