Some keys on my laptop are not working properly

Hey everybody,
I have a problem with my:shift,z,c,b,n,spacebar,ctrl,alt,up and down arrows and 1,2,3,0 on the numpad.In the past they didnt work unless i spammed them.Now they dont respond at all and the strange thing is that they are working in button combination, when I hold down shift,z,b and click lets say S it displays "5s".Can somebody help me with this?I want to know why this is happening and how can I fix it if possible.