1994 GA CD Player Problems

ok guys, I have a lot of questions and I hope someone can help me, I Realy really hope you can help me, lol.

I am trying to install a CD player in my girlfriend's car, an aftermarket CD player(pioneer), and i've ran into so many f'n problems.

1. her lights in her car would not come on for the longest time, they were originally just REALLY REALLY slow coming on, and then they just stopped coming on all together, so I put a new fuse in(cuz i found the other one was blown) and the lights came on and turned off when I shut the door... awesome i thought, good to go... wrong...

I took out her previous radio and unveiled her wiring harness and 3 stray wires... what the hell are these i ask? a yellow, black and red (could someone please tell me which each one is, I believe the red is the power and the black is the ground... but why are they "stray"? do i have to hook THESE up to the harness for the CD player?

when I was attempting to put in the CD player, I can't even remember what I did, but at one point, I had both black wires touching (The one from the harness and the one from the stray group of wires in my car) the CD player and the CD player came on(SO happy), but all of a sudden, the f'n red wire touched and sparks flew and I lost the dome lights, the radio power and everything else. replaced fuses for the radio and for the dome lights.... dome lights now stay On, ALL the time IF i have the fuse in.... and there is no power going through the red wire (checked it with wire tester), except on every other attempt when i turn off and start up her car after a while.

what the hell could be going wrong? i cannot get this god damn CD player wired properly and it's really really REALLY aggrivating me.... i have installed a CD player in a '91 Grand Am, '00 Sunfire, '88 Oldsmobile Cutlass Ciera, & a '97 Mercury Mystique, so I KNOW how to install A CD player... i've just never had to deal with these 3 stray wires before..... can anybody help me in ANY way, i really would liek to help her get this CD player in and i feel really bad for taking away her radio(cuz she just has a hole in her dash and nothing to listen to).....

thanks and I am available to answer ANY questions in order to further my progress with this blasted CD player

thanks in advance for any help, it is greatly appreciated