Run switches in Win7

As someone who skipped the Vista experience, can anyone give an a tip on how to use switches in the run command in Windows 7 ?

Helped my son finish his new build last week and trying to set up profiles in Firefix / Thunderbird. The usual:

firefox.exe -profilemanager
firefox.exe -P

just isn't working.
 
Solution
Typing "firefox.exe -profilemanager" into the Start -> "Search" box works fine for me. But it doesn't work if another copy of Firefox is running. If there's no obvious Firefox window open then check the task manager to make sure it isn't buried somewhere.
Typing "firefox.exe -profilemanager" into the Start -> "Search" box works fine for me. But it doesn't work if another copy of Firefox is running. If there's no obvious Firefox window open then check the task manager to make sure it isn't buried somewhere.
 
Solution