Inspiron 1525 Problems after Windows7

With Insiron1525 and Vista Home premium my work in MicrosoftOfficeWord2007 was going on fine. Somebody recommended Windows7, a much better operating system than sluggish Vista. After reformating the whole computer and suffering some inherrant losses,got Windows7 installed. I am in trouble. Whenever I type, the cursor jumps anywhere without any known reason and rhyme. This naturally is very disturbing and I find my sentence getting typed within the already typed matter. I have become very conscious, and work is almost not progressing.This is most observed in Word doc., as I work there.
I have tried all possible solutions but not succeeded yet !
Can somebody help ! This is urgent for me !!