== CLEAN HARD UPGRADE ON WINDOWS ==
General Hard upgrade instructions are documented in [http://www.postgis.org/documentation/manual-svn/postgis_installation.html#hard_upgrade PostGIS Hard Upgrade]

You need to do a hard upgrade if you are using a pre-alpha release of a major release such as the case with PostGIS 2.0
or you are upgrading from one major version to another e.g 0.*, 1.* --> 2.*

1. Create a backup of your postgis database as usual.  You can do this with pg_dump as that instructions describe or pgadmin by right-clicking on the database -> Backup.  Make sure to use "Custom" backup for format if you are using !PgAdmin III.
2. Create a new postgis database installed with the postgis version you want to upgrade to.  Note if you are using PostgreSQL 9.1 and PostGIS 2.0 -- you can use the new in psql or pgAdmin III sql window after you have created a new database
to spatially enable it. 

{{{
CREATE EXTENSION postgis;
CREATE EXTENSION postgis_topology
}}}


3. If you don't have perl on your windows box, download [http://www.activestate.com/activeperl/downloads ActivePerl] and install.  You can use the 64-bit or 32-bit version even if you are using 32-bit PostgreSQL. [http://www.activestate.com/activeperl/downloads].
When prompted to do so, choose to add Perl to your environment path and map perl to .pl scripts.

Note that ActivePerl also has packages for MacOS, Linux, but is generally not necessary for those platforms since they come prepackaged with perl.

4. Create an upgrade.bat file with contents something like this:
{{{
set PGPORT=5432
set PGHOST=localhost
set PGUSER=postgres
set PGPASSWORD=yourpasswordhere
set THEDB=mydb
set PGINSTALL=C:\Program Files (x86)\PostgreSQL\9.1
REM note the below example is if you are on 32-bit windows choose which install path makes most sense
REM set PGINSTALL=C:\Program Files\PostgreSQL\9.1\
set PATH=%PATH%;"%PGINSTALL%\bin\"
perl utils/postgis_restore.pl "mydb.backup" | psql %THEDB% 2> errors.txt
pause
}}}

5. Edit the script accordingly to your path settings.  Note that utils folder is packaged with the PostGIS tar balls
if not present in your PostGIS install. Download the tar ball for the PostGIS you want to upgrade too.  [http://www.postgis.org/download/]

6. Right mouse click on the .bat file (you may have to choose -- Run as Administrator)

7.  If all is working -- you should see a screen something like:

{{{

}}}