On my HP Pavilion I noticed that the hard drive flashes briefly about 
once a second while I'm using the computer. If I'm typing or moving the 
mouse, a typed letter is often missed, or the mouse will 'stick' and 
then 'jump' as soon as the hard drive activity is finished.

I have an old Compaq Presario that has simillar hard drive activity.

Is this common or do I have to reconfigure/remove a piece of software to 
stop this activity from happening?

TIA,
Mike