Hey Kris, I'm surprised that you haven't kicked that fucking thing yet.
It looks like you have some bad vibes in that apt. What type of soundcard are you running?
If after trying out DAF's suggestion the problem continues, here are a few other suggestions.
99 times out of a 100, clicking & popping & skipping etc is caused by bad soundcard drivers, or IRQ conflicts where the soundcard is sharing the same Interrupt Request as another conflicting item of hardware, such as the videocard or internet/network adapter. (LAST WEEKS PROBLEM!)
If you just can't get rid of the crackling, try moving your soundcard to another slot, as far away as possible from other devices. I would put it in the last slot at the bottom of the available slots .
Check for resource conflicts. If resource conflicts are present, try resolving them by assigning different resources / IRQs / DMA channels to each piece of hardware. Check Control Panel -> System -> Device Manager for existing conflicts. Shared resources, such as IRQs, usually don't hurt in conjunction with modern hardware, but generally, it's better if each device that requires an IRQ, has its own, dedicated IRQ.
If your soundcard shares an IRQ with another device (e.g. networking adaptor), try resolving it by assigning different IRQs to each device. If Windows does not allow you to change IRQs, then you will either have to reserve the IRQ in your BIOS setup, or try move one of the cards that share an IRQ with eachother into another slot.
This might help you out some if necessary, if you have any questions let me know.http://www.helpwithpcs.com/upgrading/change-irq-settings.htm