well i took my cd player out so that i could get it to fit right and now these a problem. i put it back in and it wouldn't turn on. so i put the red wire and yellow wire together and it comes on but when i turn the car off and than on it resets everything. any help would be good. by the way its a 96 sunfire.

Sounds like you lost your continuous power. check your radio fuse.... that is probably the problem. The reason why it works when you connect red and yellow together, is the yellow is "memory" and red is "turn on". Your "turn on" wire works, but the "memory" does not. Causing your presets to erase.

sounds like it to me,
installed a radio 5 years ago and could not find the switched power, so we installed it using constant power, not my car, but was a pita.
anyway, it is will most likely be the fuse, imo

The red wire is the one wired through the ignition switch. For some reason, both the red and yellow wires have to have juice going to them for the radio to come on. It definatly sounds like you don't have power at the yellow (memory/constant). I'm not 100% sure, but I think the fuse in your dash is for the yellow wire and the red power wire uses the fuse in the back of the stereo. The only reason twisting your red an yellow wires together makes your stereo come on is because your power wire is now sending power to both wires going to the stereo. Once the key is off, there is no power at all to either. Try replacing the fuse, and if that doesn't work, make your own connection for the constant using a new wire.