Booting without the battery usually doesn't have an effect on CMOS settings they are usually in NVRAM. But there may be a CMOS reset jumper that you set boot for 5 sec, then set back and reboot.
Here is what I normally do when I'm not sure how the serial port is configured.
Start with N-8-1
Start Baud at 2400bps and slowly work up from there
Change cable from null modem to straight pass-through
Note which way (nullmodem/passthroughI if I get garbage
(garbage is good, it means something is coming out)
Press enter a few times when booting with a new baud setting
(some systems need to be told to start speaking)
Other than that sounds like you are in the same boat as some
of the Peg][ owners that have had chips smoke, and DOA boards
from dealers. (Hope not)
Best wishes
-Shawn
No more peg. :(