Why my Nokia 6555 not playing online 3gp or YouTube file?

You have to check out the extension with the file. If the file includes some other file with other video format it cannot be played. So first check the format of the file completely. If you feel you need you can also check the format of the file by using computer and also you can convert these files which are not playable on the phone to the format which is playable in your phone according to your preference or else there might be something like the application is not supporting and it is not able to play the video file then you need to use different applications which can help you to play the videos on your phone. Few of them are like smartmovie. You can use SmartMovie application it supports 3gp avi and also flv formats. So you can try for it. Moreover it can easily install on your phone and it does a great job by playing videos with high quality. You will love it. You can enjoy the quality videos by converting. You can download it from official website.

You have to check also if your phone is having any virus. You need to detect it. You need to download the antivirus software from the net and scan your phone. Chances are also like the adobe flashplayer you have downloaded may be corrupted. So please check that also. Thank you.