Some help here for what it's worth... First all the downloads are here: http://www.3dsystems.com/shop/support/cube/downloads

Second, (and you may have already done this) but don't bother with the USB stick that came with the cube, it's crap. Any USB will work. If you've tried that and it's the USB port, you're largely out of luck as 3DS doesn't provide components for the Cubes (they do for the CubePro... but I can't vouch for any cross compatibility of electronic components). That's said, it's a USB port and you may be able to source a replacement elsewhere.

That's about all the help I can offer at this point unfortunately. If you want to keep it running, there are people unloading them at VERY low cost online. May be good to keep an eye our for parts alone. Or... turn it into a planter and buy something else.

Good luck!