i have a PC running vista that is hooked up by a ethernet cable to a wireless router.

up untill last night my macbook would conect to the web though the airport card to the router and would show the PC under "Macintosh HD" and i had set up file sharing on all my PC drives (hard disk and DVD drives that worked a dream), but today it has stoped showing up?

i have tryed GO>Connect to Server> and putting in my static IP for the PC but it just comes up with "conection failed"

i also have Remote desktop and using the same IP have no troble taking over the PC from the Mac, but really want my file sharing back

Please help

MacBook 2GHz Intel Core 2 Duo Mac OS X (10.5)