Re: BOSCH OVEN HBA76B650B/03
if the oven is noisy after you switch it off then yes I would agree the cooling fan sound likely
as for the light sometimes when the lamps go the go with a pop and this can blow some of the circuits in the oven. Since yours is controlled by a circuit board then this would need to be removed and look for blown tracks on the underside of the board
if you knowledge of electrical fault finding is low then you may need a professional to look at it
if it needs a new board then its around £90 for the part unless it can repaired
also deleted your other post on the lamp as it duplicates things
Dave