Did I kill my Mac?

[goldweller]

I'm running a Dual 2.5 GHz G5 with OS 10.3.9 Recently, I started having problems burning DVDs from DVD Studio Pro 4. After chasing many possibilities, I replaced the Sony DVD burner with a Pioneer DVR-111D. To my dismay, the system profiler showed that this drive is unsupported for burning. Googling this issue took me to this forum where some other folks were experiencing the same issue. Based on recommendations posted, I attempted to use DVRFlash (no luck), then tried PatchBurn 3. Now when I attempt to start the mac, I get the gray screen with the "You need to restart your computer...." message, but repeated attempts only get me to that same screen.

What have I done to myself?

Thanks in advance for any and all help.