I had the same problem with my Toshiba C675D. I had to use FN, Shift to get the @ symbol to come on. The numbers 1,2,3 & 4 did nothing. Also had to hold FN and then space bar to get the space when typing. I went nuts, scoured boards. Then I found one that actually worked.
1. Uninstall driver for keyboard & Mouse
2. restart laptop with mouse disconnected.
3. Try typing it should work
4. I did this; I went to local store and picked up a new Logitech wireless mouse.
Connected and everything is OK. Cost was about $10.00.
Home this helps, I know how frustrating it can be. Just wanted to share some simple advice that worked.