Hello fellow travellers in the world of Skyrim! Like you I am having a lot of fun although I have had to replay a couple of sections several times, largely because of an expired but now reconditioned Xbox 360 (kindly fixed up by Microsoft free of charge despite being over four years old and well out of warranty!).
I am here seeking help. I have acquired Viklas's sword as a a result of expressing an interest in joining the Companions, but I cannot find the person to whom I have to give it for sharpening: the problem is that I am not allowed to simply discard it and I need to do so to get into the party at the Thalmore Embassy.
Any pointers greatfully received.
POSTSCRIPT Problem solved: I tracked down Eorlund at the Underforge.