Your OS? Scrolling what; web pages, email, Explorer? When did this start? If you're running Windows (you didn't say) have you tried System Restore? Details, details . . .
I fear I may have a virus, though, anti-virus software tells me I don't. Scrolling is jerky and erratic on two of my laptops, (compaq evo n600c and Dell 1505). Can someone help or give advice?