I'm going to have to send my hard drive to seagate to get some warranty service done (aka replacement) and want to have it wiped before it goes. Will I be able to erase the drive even though it has many bad sectors?
I'm sure you will get an error report. Eraser may still run OK and perform a disk wipe, but you may get an error at the end along the lines of "completed with errors", something like that.
You may as well try doing it, I can't see that you've got anything to lose as it will either work, or won't! Of course, not all data will be wiped as the sectors with errors won't be touched, I believe.