I have a Runco DTV-947 CRT projector. It was running beautifully and then suddenly it is now extrememlt dim. I have the brightness and contrast pushed to

SOURCE: proector image is dim

I have changed the bulb on my LG projector recently. I found the rotating colour wheel to be full of dust. Upon opening the cavity where the light is redirected and reflected onto the imager, I saw all mirrors also had a layer of dust. I don't think it was so dirty that it affected the brightness of the image, but I cleaned it anyway using an earbud. I cleaned both sides of the color wheel as well. You need to be careful in working with the optics of the projector!

SOURCE: low brighness

This sounds more like a Lcd fault than bulb after such a short time after bulb replacement ,however I did have this come up once and the customer had kept his unit in a cold place then took it out to use hence due to the heat from the lamp Condensation dulled the mirrors .After they warmed up all was ok untill the next time solution I told him to store it somewhere warm .. havent heard from him since except for his stereo repair , and you don't want to know what the fur substance in that turned out to be lol
if it is an lcd fault you may find a replacement of ebay a cheaper solution ... Regards Vortash

ps and the beauty of that is you could sell your old unit minus the bulb as spares and repair and get some of your money back you just spent on the replacement .. lol

SOURCE: have a DTV 947 projector

That means you might not have computer (desktop/laptop) connection setting to projector. Cable from laptop to projector might be set but you need to do some settings to have movie shown on projector screen.
Here is link to show the setup
http://www.dummies.com/how-to/content/how-to-hook-up-your-laptop-to-a-video-projector.html
Each projector is different. You might want to press Computer on projector remote control to show PC/computer connection. You might also want to press fn+f8 key if you have Dell laptop to have image from pc/laptop transfer to the projector.
Thanks