Maarkr posted a
thread last week with a checklist for doing an new installation (very comprehensive list!).
FWIW, unless you are replacing a hard drive, a fresh install may not be as easy as:
1) uninstalling (or install elsewhere) things you never use (free space)
2) disabling process/programs from automatically starting on boot (trim machine processes)
3) if you uninstall things, using a utility to verify registry entries are removed (also trimming Win7 overhead)
I have had Win7 installed over 2 1/2 years now and would not even consider a re-install unless I was forced to do so.