Sound mystery

[RetroMan]

I've been having a problem with my studio monitors that I've been putting up with for years now, but it's starting to get a little annoying.

I have two Yamaha studio monitors hooked up to my computer - it's a matching pair and each one is self powered at the wall - when I turn my computer on and XP boots up, I only get one speaker working, then I discovered when I RESTART from the Start/Turn Of Computer/Restart option, it boots up and both speakers then work?!? I have to do this each time I want to fire up my monitors and like I said, I've been doing it for years, bit I should stop being so lazy and try to work out how to get both of them working on first boot-up

Does anyone know what could be causing this problem?? my system is a 2.41Ghz AMD Athlon64FX 1GB RAM
and my soundcard is a:
Creative Audigy2 ZS with external breakout box

The speakers are in the small stereo jack 'line out' in the back of the soundcard itself, not the breakout box itself - I thought his was the problem, but there is no 'line out' jack on the back of the breakout box.

If anyone has any ideas how to solve the mystery it would be greatly appreciated.

 

[cusebassman]

Swap the speaker inputs. i.e. take the Left and Right outputs from the soundcard, and swap which monitor they run to. If you get the same problem on the same speaker (which now has the opposite side's output running into it), you'll know its the speakers. If you switch the outputs and the problem switches speakers, its something wrong with the soundcard or another part of the computer portion of the audio chain.

I suspect it is the computer - either the OS or the soundcard.