my son used my laptop last night and now over 1/2 of the keys dont work. he

says that he didnt spill anything on the keyboard, but i’m not sure.I have a Dell Vostro 1000. The keys that do work are `,5,6,-,=,a,s,d,f,g,j,k,l,;,enter,z,x,c,v,m, “,”, and .
HELP!