E4300 Line-in recording from mixer

I have an E4300 with Windows 7 and Bios A07.

I am trying to record the sound coming out of a mixer and going into the line-in jack. I use a cable which has the RCA on one end, and 1/8 inch on the other. I used MixCraft to do the recording, but
the sound is terrible--it's really noisy.

I used to do this with my old Latitude X300, and the recorded sound was just fine, so I'm wondering what's going on now.
Is it my sound card? I made sure to disable the internal mic, so I know the sound wasn't going in through the mic-in.

 

Well... seeing as how it's a business laptop, it's not really going to be the best for anything audio related. Basically, the sound card, mic, and speakers are as good as they need to be for a business user. Very basic.

Or maybe I'm way off base and it's another issue totally.

 

You'll need a USB or Firewire interface. The soundcards on the latitude range are useless for recording. They are fine for general use though.

Something cheap from m-audio, lexicon, digidesign, presonus, etc. That will do the job.

 

It worked terrifically with my old latitude X300. That was a business machine too. If I can get that old quality back, I'm happy. My question is why is the quality so different between the old and new latitudes? It's not just a little different, it's unacceptably different.

 

If someone can tell me yes, the sound card has been downgraded in the newer Latitudes, then I'll be happy to get a USB interface or something. But I want to make sure first that it is not something else.