updating squeeze to wheezy

[John Lindsay <jclindsay@kw.igs.net>]

Greeting

I have been trying to update my Debian 6 (squeeze) to Debian 7 (wheezy). 
I have been reading the following URLs and trying to make sense of them 
with respect to upgrading.

> http://www.garron.me/en/linux/upgrade-debian-squeeze-wheezy-6.0-7.0.html
> http://www.howtoforge.com/how-to-upgrade-debian-squeeze-to-wheezy
> www.debian.org/releases/stable/i386/release-notes/ch-upgrading.en.html#backup
> http://www.cyberciti.biz/faq/howto-debian-linux-upgrade-6-squeeze-to-7-wheezy/
> http://www.pontikis.net/blog/debian-upgrade-squeeze-t
I've done a backup (nothing is critical on my system though). I have 
modified my /etc/apt/sources.list from squeeze to wheezy.

I've followed the instructions (primarily from www.howtoforge) and did a 
reboot.

Typing uname -a

I get

Linux debian 2.6.32-5-686 #1 SMP Sun Sep 23 09:49:36 UTC 2012 i686 GNU/Linux


Typing lsb_release -a

I get

No LSB modules are available.
Distributor ID:    Debian
Description:    Debian GNU/Linux 6.0.6 (squeeze)
Release:    6.0.6
Codename:    squeeze

Obviously it failed to upgrade to wheezy. Any hints/suggestions/hep 
would be appreciated.


John