Had a similar problem with Shift “p” in order to print “P” I get “P&$@#!” instead and I get 74231 if I try to type “p”. The backspace also gives me sometimes 74231 and the cursor jumps to the begining of the line.
I actually had replaced the battery short time ago with a higher and stronger battery because there is no battery similar to the original one. It looks like the new battery fried the laptop.