Win7 ultimate cant connect to xp

I understand this question has been asked and answered hundreds of times but i still need help.

I have 3 machines running XP and one desktop running windows 7. I have had the Win7 machine over a year and have hardly used it due to not being able to see the xp machines.

The win7 machine was initally running home premium and i was told by a number of people that home premium would not being able to connect to XP machines and i would need to upgrade to proffesional or higher. I reluctantly purchased an upgrade to Ultimate but am still have the same problem.

One of the XP machines is used as a storage centre for media, files etc and also has printers and scanners connected to it. all of the xp machines can access drives and use printers and scanners but win 7 machine won't even acknowledge they are there.

I need simple plain english solution as i have found myself struggling to understand some of the other solutions i have found on the web.

Please help someone or i think the win 7 machine will end up on Ebay!!!

Okay I'll try. No guaranties though!

First you need to name or rename the Network that the XP computers use to Workgroup. Not "pmh home" or anything else. Then remove W7 from the Homegroup. (For W7 computers only) Then see this. Share files over a network
Forget the part about creating a share folder for now. And in the mean time put some file in an xp machines public folder as a test to see if the W7 machine can start to see that network .Try all this and post back. If it works then we'll get into specific permissions.

I have renamed the network names to workgroup on xp machine and win7 machine.

We then fall at the next hurdle. In the previous post it says i will find a list of computers under network. Mine is totally blank!

Any ideas?

You are not seeing something like the picture below?
Can you post the brand and model of the router and explain how each computer is connected (wired, wireless etc)?