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#11
Wamsert, there is only one way to do a clean install. Clean Install Windows 7 - Windows 7 Help Forums.
If you have more than one disk, you should detach ALL other HDD's and SSD's (Very important) or you can end with the boot loader on one disk and the OS on another disk.
On OEM computers (Dell, HP, etc) there is always an easiest way that is the Factory restore. It will format the C: drive and install a disk image from the Recovery partition.
If Windows isn't working well you can do a Repair install (must be started under Windows). It will keep all user data and programs (also all trash) and reinstall windows. Repair Install - Windows 7 Help Forums
For the updates MS releases SP2 for Windows 7 - Windows 7 Help Forums