Whenever I try to record a track on the computer, it always plays back slower and almost a full step below the pitch I was playing. Even if I am not recording (just plugging a guitar into the line in and playing through the speakers), the sound comining out of the speakers is almost half a second behind and, once again, a full step flat. I'm pretty much a moron when it comes to computers, so the soloution is probably something increadibly stupid. Here's the set-up as best as I can desribe it:

Guitar>Half Stack

Pre-amp out>Line in (using addapter cable)

Any help anyone could give me would be greatly appriciated. Thanks in advance.
make sure your project rate is set at 44100
Setting this at something else may change the playback speed.

Also you should look into an audio interface when recording. It will give much better results and less latency.
Maybe you've discovered a new effect.
The below is false.
The above is true.

*world implodes*
its a computer problem, but what I'm not sure...
The software all acts the same, and the instruments cant be the problem...

Have you tried using any type of audio interface to see if that works better?