Can't import music into iTunes?

I've had this problem for months now and it's really bothering me. I'll put a CD into my disk drive.iTunes recognizes it. Sometimes I change the info on the songs (like if they're untitled I'll add a title), and I'll hit Import CD and it'll import. When it's done I'll eject the disk and the music will (most of the time) appear in my iTunes library. However if I close out of iTunes and come back to it later, everything I supposedly imported will be gone, like it never existed. At first I was just trying to import some songs from some recordings I had made, but today I was trying to import some Pimsleur lessons so that I can use them on my iPhone. This is starting to make me very mad. Does anyone have a solution for this? (I have a PC running on Windows 7, by the way.)

I never rip using iTunes - just WMP set to MP3, then import from there. This way, if I ever give up my iPod for another device, I know I will have greater control of my media.

Otherwise, there's an iTunes option to copy songs that are importing to iTunes - apparently it's deselected on your computer. It's probably an option for people with limited disk space who just import from Cd to put on their iPods and not their PC's.