AVG scan says my computer has no virus or malware, but I can't type anything.?

All keys when pressed once, type either nothing or the wrong thing. When held down, they type the right thing, but a bunch of it. Can't even log in. Went on guest account but still can't download stuff or make system changes with admin password. Tried holding down and then erasing till I have one character, but the backspace key also only works when held down and I'm finding it extremely difficult to hold down and stop just in time to delete all but one of each letter. Please help

?2018-11-17T10:19:14Z

Try the simplest thing first. Borrow a keyboard that is known to be working, plug it in and try that. If it works, clearly the problem lies with your own keyboard. You may want to try cleaning it or simply get another.