General

@Regatzopunk Ok, the problem is that the "CD input" is for connecting a CD player to the amplifier so you can listen to the CDs through the amplifier's speakers.
It's an "INput", meaning the sound goes IN to the amp, no sound comes OUT of those connectors, it's just for sending sound IN to the amplifier.
You can connect other sound sources to that input and listen to them through the amplifier, but you can't get sound OUT of the amplifier through those connectors.

Try this- plug the cable from the CD input on the amplifier to the laptop's [b]headphone[/b] socket.
Then play something on the laptop (music, a video, whatever as long as it has sound) and you should be able to hear the laptop sound coming out of the amplifier's speakers.
You might have to set a switch on the amplifier to "CD" or "Aux" to hear the sound from the laptop.

Now if you plug the microphone into the laptop's mic socket, you should be able to record the sound from the mic on the laptop, AND hear the sound from the mic on the amplifier's speakers.

You might have to adjust the Windows volume control settings to turn up the microphone volume in Windows to hear the mic and be able to record it on the laptop, but that hookup should do what you want.

@BobR: Ok so I have an amp with the 2 RCA holes in the back and it says CD input so I connect the cable there and I connect the other side which is a regular audio jack to the microphone hole in my laptop. In the front of the amp I connect my mic and then I play any instrument like guitar or drums and it is supposed to amplify the sound, but the problem is when I connect the amp to the laptop I get the bad sound. It has nothing to do with the mic because I get the sound even without mic plugged in. So I think that the 3 possible reasons are 1) You can't connect an amp to a laptop in the microphone slot because amps aren't recording devices. 2)The cable I'm using isn't good enough, or 3)I'm doing something wrong

[quote=Regatzopunk]@bobr yes well not to record singing but yes the same concept it's to record through the mic on laptop by feeding through amp[/quote]

What do you plan to record..?
A microphone is only used to record voice, live music or singing. A "line in" input is used to record things like music from other sources like MP3 players, radios or CD players.
It makes a difference because a microphone input has to be a lot more sensitive, and connecting the wrong device to the wrong input can cause really bad noise problems, kind of like what you described.

Also, you have to be careful about what's an "Input" and what's an "Output".

You said you're connecting an RCA "Input" on the amplifier to your laptop.
Depending on what socket you're plugging into on the laptop, you may actually be connecting it to play the laptop sound through the amplifier instead of getting the laptop to record whatever is on the amplifier.

You need a connection on the amplifier labeled something like "Line Out" on the amplifier to send the sound OUT from the amplifier, and a connector on your laptop labeled something like "Line In" to send the sound IN to the laptop for it to be able to record the amplifier sound on the laptop.

@bobr yes well not to record singing but yes the same concept it's to record through the mic on laptop by feeding through amp

[quote=Regatzopunk]So I really need urgent help[/quote]

First thing, you need to explain exactly what you're trying to do.
Are you trying to record the microphone on the laptop by feeding it through the amplifier..? Like to record singing into the mic..?

The mic isn't the problem, I don't even connect the mic to the amp and I still get that awful sound D: @nonsonofronz

You probably can't connect the mic directly to the amp.
Also, are you really close to the amp with the mic? You might just be getting hella feedback since you're so close.

If I could see a pic of your setup, I may be able to help.

uhh i don't think you can feed the mic through an amp