Mostly likely, the power supply, which is in the subwoofer module, has blown. This means that the entire unit is pretty much worthless.
The speakers, by whatever chance, appear to be pretty much industry standard, and could hook up to a proper 5.1 (or better) AV receiver. Not sure what their load rating is. Probably 4 ohm, but that shouldn't be a problem for any well designed receiver playing at reasonable volume. So, you would need to go on the hunt for a new/used AV receiver which fits your needs. Lots out there on Craigslist. If this is just hooking up to your PC, then an older non-HDMI model would likely be fine and may be under $100.
But, your subwoofer is dead. I expect you can toss it and get a new standard (powered) subwoofer of your choosing. Price can be all over the place on them.