when doing installation postgis on windows 7 manually, You may encounter a problem when
"create extension postgis" is operated.
pg may complain some errors about insecure usage of backslash quote in client programming
a simple solution is :
find out postgis-2.0.x on your_postgis_path/share/extensions/
remove all \'.
\' in my case only appear in this block:
IF format != 'GDAL' THEN
RAISE WARNING E'Format \'%\' is not recognized, defaulting to GDAL format.', format;
END IF;
running "create extension postgis" again, it should work now.