Laptop keyboard problem

Please help. When I type a message, my keyboard letters jumped all around and enter past words that I have typed. I have switched keyboards and it does the same thing. I am using a Dell laptop with Windows7 and intel Pentium inside.
My original sentence before I made corrections read "The quick brown fox jumped over the lazy dog."
This is the way the sentence looked before I made corrections "The quiwnck bro f.fped ogver the lazyx o jum do
 
Check if your antivirus is updated and also check how old is the keyboard... sometimes in this cases keybopards just stop working after their calculated lifetime.
 
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