My computer won't boot, says windows/system32/config...is corrupted, what do I do?

OK lets deal with recovery of your files first, cos if you follow the other answers you lose all your work. You have another computer so that's half the battle. If you are confident enough do as follows, if not get a mate who is good at computers to help. Buy a USB hard drive case, they are not too dear. Remove the hard drive from the duff computer and put it into the USB case. Connect that to the other computer and transfer the files, preferably to a folder, (call it back up or something you will remember. Now put it back and you can reinstall Windows. Unfortunately if you have no disc you would have to buy a copy of Windows as it cannot be downloaded legally. Good luck