starter problems ?

for the last couple of weeks, when i start my engine it makes a weird scrapping sound, the same sound as if you turned the key when the engine was already on. do i need a new starter or is it some other reason. also when i have my engine running on idle in drive or neutral and turn on my air, the idle becomes rough up and down and starts dipping so that it starts to shut off my stereo and dim my lights. what is wrong with my car ?!

n e one ?

Might have a damaged/dieing alternator, have it inspected