First of all, if the date on a computer is September 10, 2003, or later, this worm will no longer propagate. Sobig-F is no longer much of a threat after this expiration date.
Sobig-F is a worm which spreads via the Internet as a file attached to infected e-mails, as well as through shared network resources. It does not exploit the RPC vulnerability mentioned. Installing the Microsoft patch will protect against other worms and viruses, which attack the RPC.
As a general rule of thumb, each time you patch a system, you reduce the number of attacks, which can succeed.
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This was first published in September 2003