My camera doesn't have color and I constantly see horizontal lines how can I fix this

To avoid to much guessing, I think you should try to reset the camera. How to do that is on page 24 and 25 of the manual. With this you exclude things that can go wrong, because of a wrong scene setting or white balance or whatever. After you did the reset in the shooting mode, everything is in automatic again. Then again try to shoot a picture.

It could be the display is giving up. after a few years you can't expect it would work as new. So even if you still see lines on the display, shoot some pictures and put them on the computer. There view the results.
If the pictures are good but the lines are still on the display, try to live with that. Repairs will cost more than a brand new camera of a better quality. If the lines are in the picture, the sensor is defect and I think you should start saving for a new camera. Although new point and shoots can be bought around a 100 dollar. But even some smart phones now can take pictures that should be as goos as the ones that came from your Olympus when it was brand new.
If you can't find the manual, the link here will download it for you:

http://www.olympusamerica.com/files/oima_cckb/Stylus_850_SW_Mju_850_SW_Instruction_Manual_EN.pdf