The CPU turns on but no display on monitor, no OS initialization observed, any idea?

check whether its num lock on keyboard is alive after please pen case and examine Ram module by changing with new one .if cpu is giving beeb  with out ram please count beebs and search on google about relevant beeb count.check process is heating up .is there any capacitor blow ?

physical examine all parts for damaged

If no display on screen, most of the time is because of your RAM has not properly seated or there may be a problem on your RAM slots. Remove them first and clean your slots and the ram. You can try inserting 1 RAM at a time to check where (slots) is the problem.

Note: Be sure that you will discharge the static electricity after cleaning both. Static electricity may damage your PC. One way i always do is blow an air on my hands and hold the ram before inserting it back to the ram slot.

hi my friend

cheack on ic display verify

and verify capicator

and verify ram

first check ram properly inserted check it if out of place replace ram after turn of computer and discharge static electricity.Than start computer if there is no display than turn of computer again n remove ram and clean the slot and ram than replace it and check display again if again there is no display remove cmos cell for one minute then replace it and check display if there is no display again than remove old ram and insert a new one and check display if again shows no disply there is VGA chip problem on board then insert a vga card  and check display or send board for repair to company.

There may be two problems; First would be the problem with RAM and other is Processor.

If you have 2 RAMs on board then remove one and try to On the system if problem remains then plug on the first one and try to on the system. If both RAMs not working well then remove both 2 and on the System.

second thing If you have checked you RAMs on board and then try to remove Processor and try to on the system if problems remains so I am afraid that you system's board is not working properly.

Minor chance of Graphic card issue possible but so try to check the system with new Graphic card or LCD. 

First, we have to make sure that all connections are tight and well connected. If still has no display, check the inside connections of the system unit will be the next thing to do. We have to check all the parts like the motherboard, ram, and lastly, the monitor. Connecting each part to a full functioning computer would be a good testing technique. In case that there is no other computer, disassembling, cleaning and reassembling is the next step. If the problem still exists, it may require to bring the system unit to the nearest computer repair shop so that the problem can be identified after testing each part.