So yea, why does it randomly give me this error? I've reinstalled it and nothing works. Any ideas?

Why does blizzard release a patch that does things like this... it was working fine... since 9 years ago.

lol okay if you have a valid CD-Key then use the CD, then install the latest patch (use google if b.net dosen't work or you can't go onto SC )

If you Copied and pasted SC from a computer that had it installed and to one that DIDNT have it installed, itll give you this error.

My suggestion would be to just install it the ol fashioned wa, or find some CD Images (Im not getting in trouble you find em yourself xD)

sometimes this happens when patching, particularly on linux (Wine) and OS X (since the game came out in the OS 9 era) but it is also known to happen on windows sometimes. the way around it is to uninstall everything (bnet and sc preferences included) and then reinstall the game. DO NOT go on Bnet to update, instead do the manual install with the patch from the blizzard support page. then you can play normally.