Hang up

Hi, I have a system with High configuration and NT4 with SP6 installed. It recently has developed a problem, mouse struck for 3-4 seconds while moving. I thought due to dust in ball or mouse settings problem could be the cause and cleaned dust and reset all mouse options to my requirements. Though it did not solve I rectified that keyboard also hangs during that time. I thing it is a system hangup for 3-4 every now and then(say 8 to 10 times in a minute) because of which i cannot continue using it without intruptions. Can anybody find the problem and solutions for me????