I sort of assume, though GUEST didn 't say, that the recordings were his own(as opposed to commercial recordings)--also, it isn't clear what GUEST wants to do with the digital recordings--do you want to make CDs for listening, are you going to archive the tracks on CD and get rid of the tapes(a bad idea), or do you want to work with the tracks digitally?

Converting finished analog recordings to digital is relatively simple, but if your recordings are raw 4-track, you will have to do some sort of analog mixing before you feed it into your soundcard--(I am a Mac person, and not real familiar with the hard and software involved here, but I doubt that your laptop will allow for four analog tracks in, or that your software can accomodate them) making this a bit more involved a process than you might want to try to do, at least until you've gotten more familiar with your new computer--