My computers power SUPPLY was recently ruined after a power outage, and when I replaced it with a new one everything was fine except the audio.
The problem is when any sort of bass instruments starts playing it creates some fuzzy feedback or static, otherwise when there's just singing or any normal music without a beat there's no problem.
So is this a sound card issue or something that can be updated with firmware?

I'm running Windows XP service pack 2 and my sound card is a Sound BLASTER Live! 24-bitHave you tried another set of speakers ? ?
They may have taken a spike as well.Have you thought about getting a UPS (Uninterruptible Power Supply), i.e. a battery backup unit?  It's a wise investment to protect your COMPUTER against the damage that can result from such power outages.  I dont think it's the speakers as my heaadphones have the exact same problem with the bass.
I was also using a surge adapter but it's got about 6 things plugged into it and it was a very hot day and a lot of electrical thnigs were on that day. Perhaps you have a damaged sound card.  Run dxdiag (Start, Run, and enter dxdiag) and run it's sound tests.  What are the results? 

Open DEVICE Manager and see whether it reports all sound devices are WORKING properly.  Does Device Manager show any yellow triangles with exclamation marks, or unkown devices?

A surge protector does not provide as much protection as a UPS.  A UPS not only provides protection against surges but also provides protection against drops in power or complete power outages.  In other words, they provide a smooth flow of power and will keep your computer running, even if a complete power outage occurs.  This gives you time to do a proper shutdown, or the UPS software will execute a proper shutdown if you're away from the computer.