Logitech Z-5300 - No sound form center and FL

I gave up on this a few months ago but have got my other 3 speakers out today to try and get them working again. This sound system was bought for me last xmas to go with an Audigy 2 OEM. I get no sound whatever from the center and front left speaker. Everything appears plugged in correctly and my sound card drivers have been installed (I have also tried 3rd party drivers). The speakers themselves are fine as they work in other speaker inputs. The rear and front right speakers function correctly, as does the sub. I thought this was a software error but I'm beginning to fear it's hardware. Nothing has ever happened to the speakers though and the wires and jacks all seem okay. Well, I'm fresh out of ideas so I'm posting here. Any help would be appreciated greatly.

Thanks!

Windows XP SP2 (Everything is bang up to date because I just formatted)

CPU: P4 @ 2.4g
Mobo: IS7-E
Mem: 1024 3200
Sound: Audigy 2

Have you checked that the speakers are in 5.1 mode? Go to Creative speaker settings and then check that 5.1 speakers are checked. Also check the XP's Sound and Multimedia Control Panel is also in 5.1 Surround Sound.

Failing that, have you checked the balance in the creative volume control -> Ensure that the yellow dot is dead in the center and that the subwoofer and center speaker volume are turned up to full. Also ensure that the Windows Volume control settings are all correct - check every input to ensure the balance isnt tipped towards the right speakers.

How do you're speakers connect to the soundcard? Digital or Analogue?

PC Spec: AMD Athlon XP 2000+, ECS K7S5A Motherboard, 768MB SDRAM PC133, Sparkle nVidia Riva TNT2 M64 32MB AGP Graphics Card, Creative Sound Blaster Audigy 2 6.1, Windows XP