Thank you, Publius. I hope you are well.
You seem to be correct about sdb. I chose it to boot, via the BIOS ad hoc boot menu, and first a line came up saying no grub file, but then the grub menu came up properly.
Now here's the problem, and I don't know where this came from. Both this grub menu and the one I access via the Win7 BCD via chainloading will not load PCL. I get a "no such partition" error, even in failsafe, citing hd 2,1. That would make sense, since that is a windows storage partition, and PCL is on sdb2.
So I fired up the PCL live disk in order to access menu.lst, only to find that while the file manager shows it at 699 bytes, kwrite shows it empty. So I don't know how to get into that menu.lst, which I believe is a simple text file under Grub1, and change things.
To my original query, I really wish there was an option for grub not to write to ANY mbr, but that's not my immediate problem. I need to correct the partition spec, and I'd rather not run the install again, as I don't like the grub function here and this is my main machine.