Follow the wiki, a clean install of Windows which may be found in my signature below. It will take you through everything step by step.
Dell Inspiron N4010 32bit running Windows 7 Home premium   I would like to wipe my laptop, as it is running slowly and poorly and cleanup to have a fresh OS and HD.   I have the Drivers and utilites disc that came with the laptop. How can I get Windows 7 reinstalled on the laptop? Someone mentioned that their is a product key taped to the back of the laptop which is still their and readable.   Anyone point me in the correct direction on how to do this reinstall and cleanup.
Wipe computer and reinstall OS and drivers/utilities