In-built flash stuck in up position
Indeed: "which camera" would be very useful starting info!
Anyway, years ago on a 10D I had a similar problem, and it turned out that the hook that goes down into the body couldn't engage because a wire had got out of place inside. Not that this is the explanation for your problem, but I can't think of anything better than to say "take it to a repairer".
|Dirt Hose by poppyjk|
|European bee-eaters by drvanger|
from A Big Year - birds
|Fat Is Beautiful Guinea 2008 DP by MarioSS|
from - Fat is Beautiful - (Woman's Portrait n Black and White+ A Border)