can anyone tell me the meaning of "There was not anyone in the room but liked his singing" Is this sentence correct and if it is, then could anyone explain to me it's meaning.
This is an obsolescent use of but, which the OED explains as:
14 b. With omission of the pronominal subject or object of the subord. clause, so that but acts as a negative relative: That..not, who..not. (Latin quin.)
So the meaning is "There was not anyone in the room that did not like his singing."
'But' is often used this way in literature up to the 19th century, but it is rare nowadays.