Keyboard is not functioning correctly

Hello,
my keyboard is not functioning vcorrectly. bas you bcan bvsee, it puts random blettersz' such bv asz' these (bv, z, ' , and the space bar bsometimes makes the menu for a right-clicking mouse show up (i.e. the menu where cut copy paste, undo are) and sometimes pushing certain kyeys like "b" mak\yres it erase bvthe entire post or docuhgment that i am writing. i have tried EVERYTHING but it vseemsz like this z'is the work of a virus... just i75inserting gibberish i75nto my text! HELP PLEASE i am a student and this makes writing papers EXTREMELY difficult,nf i would LOVmhgE to beb vable to type things w2ithout bvbeing forced to go backyr and take out all the letters that are randomly poppo0i7ng up!
ANY HELP/IDEAS WOULD BE WONDERFUL!!!!