Uninstalling db2 v9.7 in Unix based system

su - db2inst1
db2 stop application all
db2stop
cd /usr/IBM/db2/V9.7/instance
./db2idrop db2inst1
cd /usr/IBM/db2/V9.7/install
./db2_deinstall -a
then make sure that /usr/IBM/db2/V9.7 is empty
then make sure that all subdirectories under /db2/db2inst1 are empty

DB2 Infocenter