ghost typist

HI everyone;
laptop spec:
HP omnibook vt6200
intel cel
1.4ghz
40gb

i just installed windows xp from scratch and after installation, also installed anti-virsu software (AVG and Zone Alarm) scanned and no virus found. After using the laptop for several minutes, start typing on whether on the internet, run command, / even on microsoft works one character runs through the space without even typing that character “x”. please help