Blue screen using .wav!

Blue Screen Problem
I have a problem in that whenever I try to do anything involving .wav file I get the following on a blue screen "Windows has shut down as an attempt was made to execute non executable memory" and a stop 0x000000FC error.
I've tried to resolve the problem using Direct x diagnostic and get safely through the sound checks on sounds 1 & 2, input, but come a cropper when I try clicking "Direct Play Voice options" and run the wizard, but it crashes when half way through testing Full Duplex Sound.
I've upgraded all of my sound card audio and video drivers to no avail.
Thinking back, this started to happen only after I installed a Skype phone! But I have uninstalled this, yet it is still happening.
If there are any whiz kids (or even whiz oldies) who can help, it will be much appreciated.
Am running xp+sp2