Is there a Hadeeth which talks about a person who had ONLY one strand of hair as his beard, to which an Angel was hanging, and our Prophet smiled at it? Please advice.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

After having searched the narration you are asking about, we neither found it in the available books of Prophetic narrations nor in the books of known scholars.

Allaah Knows best.