The lamp can be replaced but they cost about £250 most projectors only have 1 lamp.
These things have a lamp counter built in so when reach a certain time eg 1000 hours the projector says lamp needs replaced sometimes just removing the lamp and replacing it resets the counter,or depending on make you have to press various buttons at the same time. check the web for instructions for this proceedure for your make and model.cause the lamp might still have life left in it
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix video projectors.