Remember the bitcoin program is actually called bitcoind so it is:
bitcoind -rescan
Not quite correct, there are two seperate executables included in the distribution - bitcoind is the daemon that has no user interface, and bitcoin is the program that 99% of people use.
C:\Program Files\Bitcoin\bitcoin.exe -rescan is the command to put in Start Menu -> Run for just about everybody.
The rescan option is used when you wallet file doesn't indicate the correct balance because transactions were missed somehow (usually database issues).
Maybe try updating your firmware too.
What??