Here are some suggestions which should help. Make sure all programs are closed except the ones you are working with, although this usually is not the main culprit. Second, if you have on board sound or any other variety of that cheap nonsense that comes with computers, turn it off, uninstall it etc. For on-board, you will need to access the bios setup during start-up and disable the on-board sound. If this doesn't fix it, my bet would be the graphics card. Older graphics cards tend to use a lot of memory and resources are are generally the cause of these clips pops, just about every f up I have seen with sound cards. Go into graphics accelleration which should be under the desktop:settings: advanced panel. Turn them down a bit. Also, make sure you have your buffers set correctly in whatever program you are using. There are some decent sites out there for audio optimization, although I would say none of the services are really necessary for two track transfers. They are more geared towards multi-track recording which is ram and cpu intensive. Ho0pes this helps a bit.
Daryan