Ahhh ok..I see your problem. You need to go to the samsung site and download a program called Samsung Kies. It should allow the pc to see the computer. If thats not the issue, try to connect the phone to a different PC and see if its able to read it. That way you ll know if its a driver problem.
If it works on another pc, download the ROM you need and drag it onto the phone from there. Remember, from recovery you will need to go to "mounts and storage and then go to "mount USB storage" for the pc to see the phone.When you are done, unmount it. If you dont do this, the pc cant see your phone. Then wipe data/factory reset -wipe cache partition, then go advanced options and wipe dalvik cache. After that flash the ROM and then reboot the phone. First boot will take a few min, so be patient and wait 10 or 15 min for it to boot.
Keep me updated!
— modified on Feb 29, 2012 2:44:20 PM