Keyboard Not Working Properly

When typing numbers and some of the other non-alphabet keys (eg. arrow up) I get unusual results. 1, 7 and 8 appear as typed. When pressing 2 I get 2`, 3 I get 3§, when pressing 4 I get 4], when pressing 5 I get 5[, when pressing 6 I get 6=, when pressing 9 I get 9, but then the curser moves to the line above. There are more issues with the arrow signs, brackets and parentheses. The computer is also very slow. Do I have a virus? Is this correctable within Apple Software? Are there solutions?