Is there any hope for updating my Garmin if I don't have the original connections?

I was given a Garmin GPS for Christmas several years ago and I have no idea where the original packaging has gotten to. My system recently told me that I needed to update, and then a few hours later it flashed a picture of what looked like a pc and then promptly died. Each time I restart it, it searches for a satellite, and then dies. I’m guessing that it’s trying to tell me that I need to connect it to a computer and either update or run diagnostics, but I don’t have the plug ins. Does anyone know if the company will support such an old unit? Do I have any other options (besides buying a new one)?