Im trying to install fourdeltaone via offical installer but it says iw_00.iwd not found before it it said nothing else but i just added the dll to mw2 folder can someone help me with a fix

Did you install the full game before you ran IW4M installer?

yea first installed the game then ran the IW4M installer

Open "main" folder on your game installation and see if iw_00.iwd is there.

Either you're missing files, or you set the wrong game path.

there is no main folder could something went wrong when installing ?

Yeah... reinstall from a different torrent you used.

i didnt use a torrent legit game

Then just make a Steam check on your game installation to get the missing files.