When i play back any music mp3/audio it has a warble effect and voice level is low compared to the music.

Also when i play a DVD the audio is also very weird, background sound is far louder than voices.

I've tried everything i can think of.

Running XP Pro, Athlon XP 2100+, 512MB DDR Asus 7m266 mobo, soundblaster1024 live.

Had been working perfectly until recently.

Help needed.

It's hard to give advice if you don't say what you've tried.
Could be dead speakers, interferance in the speaker wires, dirty plugs or a corrupt device driver

I'd start with stripping out your sound drivers and re-installing. May be worth re-downloading the XP drivers from the manufacturers website as well just to make sure you have the latest.