samsung rear proj 56" hd tv?

my tv goes of every few days and standy and lamp lights flash. i turn it back on and it is ok for a week or two then does the same again.the picture is still as good as the day i bought it 14 months ago.it has been ok for the past two weeks, but will probably do the same again soon. has anyone got the same problem with theirs, and any ideas what the problem could be. thanks for any advice. cheers Tony.