hi after downing that quest i got the iron sword of ambers then the quest did not comlete
but the arrow remained on the sword even if i sell it . what to do with it ?

I have no idea what quest you're talking about but go http://uesp.net. Find the quest you're looking for and give console commands to remove the item and/or mark the quest as finished.

I'm assuming you're on PC based on your signature. If not, try reloading an earlier save and starting the quest again.

Are you on the PC?

yes on my pc the quest in when you find a dead treasure hunter and it gives you a treasure hinters note to find
the iron seord of amers on crossroads watch town (Falkreath)

http://elderscrolls.wikia.com/wiki/Treasure_Hunter%27s_Note#Quest

that is the guy, but well it says nothing about the sawrd , so you think i should use the finish quest command?

I only see one sword on the list of possible items, and it's a steel sword of cold, not an iron sword (I guess this could have been changed later). So, if you want to finish the quest I would use the console commands.

Good luck.

http://img01.imagecanon.com/img.php?view=33a678340bd2a97842eecebcc94bec84

yes that is what i thought also

and haw do i find this quest id if its not on the list ? playing this game is becoming my everyday bug !!!!!

http://www.gamesas.com/topic/1338161-i-want-to-work-for-bethesda-soft/page__p__20152948#entry20152948