Whenever im playing a video w/ GOM player it ask for the codec. please help..

Hi and Welcome to Fixya

Video Codecs are needed if in any case some videos wont recognized by your computer due to different file format. You can download free codecs over the internet and they are absolutely free. Here is the link for one of the codecs available over the internet.

Have a good one!

Whenever...It would be better for you to update the GOM player or you can try another free media player. Here are some free players for your reference.
1. Leawo Blu-ray Player
Region free Blu-ray player, free DVD player, free 4K video player, free 4K Blu-ray player, free audio player and free ISO player.
2. Kodi
In addition to physical media such as Blu-rays and DVDs, Kodi supports all of the common file formats in use today, both for music (MP3, FLAC, WAV, etc.) and video (MP4, MKV, AVI, etc.).

3. KMPlayer
KMPlayer would be able to play that file, quite smoothly & there are impressive features too. Some of those features of KMPlayer include its support for 3D, 2K, 4K & UHD, presence of internal codec file