Low Speaker Volume

No matter how high I set the volume levels, I get low output from the speakers. I'm using a SoundBlaster PCI 128 sound card.

I'm pretty sure my sister screwed it up somehow, since she's been known to put several trojans and malware on my computer... i.e. "COOLWEBSTUFF!!" folders, etc etc

Anyway, I've tried making sure everything is connected properly, and it is. I've tried plugging headphones into the back... no output at all. I've tried running the headphones through my crappy old joystick, because it worked before... but this time, no dice.

Anyone know what the problem is, or how to fix this? I'm tired of the CPU fan being louder than my speakers.

Thanks.