I have a HP Pavillion dv8000 laptop with Windows Media Center 2005.I have 1G ram and the computer is 2 years old. Several months ago, I installed a new 100G Fujitsu hard drive. Since then, if the computer is on for several days straight, it starts making a knocking noise every 30 seconds or so. If I turn it off or restart, it will stop for a few hours then start again. Sometimes I can turn it off for 24 hours, and it will come back in 3-4 hours, or not come back for several days. Sometimes it will knock after a few hours of being on, other times it may be 5-6 days before it knocks again. Only lately is it going every few hours. It is very noticeable and loud. I have a laptop cooling fan, which keeps it cool, so it is not overheating...... I've run all the scans, checked BIOS, everything. Nothing else is messing up besides the drive. I have to have my computer on most of the day for work. HELP!!!!!!