USB port is not recognized by laptop

I was making a Line follower, but then i don't know what happened and when i connected my arduino to my laptop it does not recognize any port in IDE. But still i am getting power in my arduino microcontroller( as indicated by a green light ) but LED 13 doesn't respond or light up even if i press RESET button. I am using Arduino UNO.
Please respond any sooner, I have a competition coming through so I need it real quick.

Have you tried connecting your arduino on a different computer to see if the port gets recognised?
Does anything get hot when your arduino gets powered up, that's an indication that something went wrong (short circuit, etc...) otherwise your led might have just broken.

I tried on other laptop also but I am getting the same problem.
And there was a heating caused I don't know the reason why ? But Perhaps due to that heating my circuit has been shorted somewhere.
So please tell me how can I check where my circuit is shorted or what can I do to resolve this problem ?
& this is the problem only in ATmega 328p then I can replace it but if it another somewhere then what should I do ?
there is one more thing that I came across while surfing about the solution "that my bootloader is missing". What is it ? And How can I reinstall it ?
Please reply me sooner,
Thank you.

Here's the bootloader (I don't think that's the problem):

Is the 328p heating up, that's an indication that it's broken, maybe you could indicate what's warming up on a photo, you could also try the loobback test, the instructables are on the forum.

I had a similar problem a month ago and the problem was a broken comparator, costs 5 euro but the tools needed (hot air rework station and a small tipped solder iron) cost 200 euro.

ATmega 328p is not heating now but once it heated after that my 13 pin led didn't blink ever.
whenever I give the power supply to it via USB or some battery then only green led glows not any yellow(13 pin).

Do you have any other way by which I can upload my code to arduino.
or what if I replace my microcontroller with a new one ?

I just got"error process returned not zero code: 1" like this error in overwriting 3rd program. What should I do? (In android - arduinodroid app. Please help.

Sachin: Your atmega is probably broken, replacing it should do the trick. But did you try the loopback test yet?