Toshiba dlp s20 projector

hi my projector was purchased in 2004 and has clocked over 5000 hours with one bulb, i decided to replace the bulb as the picture was deteriarating the projector ran on standard power for the last 2000 hours of its life and the unit started to not power up when switched on, it tended to whistle and the fan sounded like it was blowing very quickly, i replaced the bulb this morning and the picture has improved perfectly, although i am satisfied the unit still refuses to activate when i switch it on at first, after 2-3 attempts it runs but still whistles at first, originaly it started first time every time. have you any idea why this is happening or what can i do to ammend the problem.