Hello.
"Show stacks" command does not show information about current state - it's a history command, and is used for troubleshooting router crashes. Information will be gone after router reloads.
See description here:
http://tools.cisco.com/Support/CLILookup/cltSearchAction.do?AT=gD&BM=t&CN="show stacks"&IndexOptionId=All index OPtions&IndexId=IOS
For information about current processes use "show processes cpu" and "show processes mem". If you don't have BGP entries there, than it is not running and is not consuming any CPU or memory resources.
Example:
7206_hra_lab#show processes cpu | include BGP
171 196 858966 0 0.00% 0.00% 0.00% 0 BGP Router
173 888 406936 2 0.00% 0.03% 0.09% 0 BGP I/O
174 28172 28187 999 0.07% 0.00% 0.00% 0 BGP Scanner
7206_hra_lab#conf t
Enter configuration commands, one per line. End with CNTL/Z.
7206_hra_lab(config)#no router bgp 65001
7206_hra_lab(config)#exit
7206_hra_lab#show processes cpu | include BGP
7206_hra_lab#
Hope this helps.
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