Unable to join home network on my Win 7 laptop- Why?

Hi Chaps
your help and suggestions please. For a long time I have run 2 PC's which are cabled to a netgear modem router - also a windows XP laptop which is connected by wireless. A home network was established and all has been well for literally years.
Earlier this week I decided to flatten the Laptop and install Windows 7 32 bit - no problems in that regard, all works well.

My problem is that try as I may, I cannot get the laptop to join my home network - tried all the usual work arounds, but with no success.
1 - What have I missed?
2 - Would it be better to abandon that existing network and establish a new one?
Your thoughts would be appreciated.
Thanks

This is now solved!

Purely acting upon a hunch - I simply changed the password number and when the new passwords were typed in.... instant result. You learn something everyday!

Edit: Not needed, OP solved his problem and posted while I was typing my answer.