I do not need a solution (just sharing information)
FYI,
Quite recently we began switching to desktop machines with the "secure bios" specification and I found that I couldn't boot the Dell T1650 with theSSR 2011 recovery disk or with a custom recovery environment on a USB flash drive. I called Dell and got no useful information from them regarding the issue because they had me try booting from Windows Server installation media, which worked without a problem.
I started going through the BIOS settings and when I turned off the "XD" setting (Execute Disable, used by the OS to prevent applicaitons with buffer overrun problems from causing problems) I was able to boot from the SSR 2011 recovery media.