This is possible, if you can still solo each track that you want to be separate once in the PC. I'm asumming from the way you said 4-track master, you mean you have the original 4-track tape used for recording, and not that it has been mixed down to a pair of stereo tracks and mastered. You would have to record each track into the PC one at a time with the soundcard you have, and might have to work to get everything timed correctly once in the PC. N-Track is easy to use, and costs just about nothing if you don't already have multitrack software. Once you took the time to record each track into the computer separately you could add effects or whatever to each individual track, mix them however you want, combine into a single wav file and burn to CD.
A SB Live Value isn't the best quality soundcard for audio recording though, and you might introduce even more noise onto the tracks this way. Try it and see, but the analog I/O on my SB Live is really noisy and useless for recording purposes. The only way I use the SB Live for recording is the digital I/O, which unfortunately the Value version doesn't have. For more info on SoundBlaster cards and other soundcards search the BBS. There's lots of posts on that.
Good luck.