Re: new laptop
To do it right, you really should do a fresh install of Windows, as instructed in your user manual - it's different from brand to brand how they want you to do it. If you do a full reformat and install, you'd better make sure you have all the drivers for your laptop and the specific peripherals, or you may be sitting there wondering why your touchpad or speakers no longer work!
If you're shy at that, the go into the Control Panel>Add or Remove Programs and uninstall programs that you don't use (be careful NOT to uninstall system required programs!). Unburdening the system of programs you'll never use will go a lot further than defrag, which rarely makes a noticeable difference in how "fast" the machine runs. Then install an antivirus program like AVG FREE and make sure you don't have other nasty problems slowing your computer down.
Might also try hitting CTRL>ALT>DELETE and then looking at the processes tab. If you're not running any programs, about the only thing you should see with numbers in the "CPU" column is "System Idle Process." If you see other stuff running, check that program and make sure it's supposed to be running and not something bad that's draining your system's resources.