Help to Homegroup

From what I was told.....Both have to be on at the same time to share data.
I could be wrong so wait till you get a more positive answer.

I have same set up (laptop and desktop) but do not homegroup with the two. Using two different firewalls and AV programs.

No. My laptop is connected through the DSL router provided by AT&T Uverse.
I am using laptop now and desktop is off. Mine is not set up for homegroup.

I get my internet connection through a DSL line provided by AT&T uverse. It's a package deal that brings in TV and internet connection.
With that in mind my desktop is cable wired from their router which in turn my wifi laptop is connected.
I can use one or both no matter which one I choose to use. But I don't have a home group connection between the laptop and the desktop.
To my little knowledge of home group they both must be on at the same time to share info between each other. Which I choose not to do. If one gets infected I don't want both to be. That is why I use different AV's and firewalls in each.
Hope that explains it better Kupalski.

Follow this tutorial..
Both computer's must have the same OS/password etc...
Homegroup - Create

This problem usually has to do with the time/date settings being out of sync with the other machines.

It can also be caused by Ipv6 being turned off or the router being used is very old and can't handle the IPv6 protocol.

It's also important to remember that your machines need to have a different name in order to see each other.

Another solutions is this.
1. Click Start. Search for run and press enter. In the field, type regedit and press OK.

2. In the registry, navigate to the following key.

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters]
HKEY_LOCAL_MACHINE
\SYSTEM
\CurrentControlSet
\Services
\Tcpip6
\Parameters

3. In the right pane, right-click on “DisabledComponents” and select modify. In the value data field, type “0″ (without quotations) and press OK. If the value was set to ``FF``, it was turned off.
4. Reboot your computer and it should work. It did for me.

It's also important to note that just about any type of A/V software or third party firewalls can also cause this problem to occur.

If you are still lost you can try going through this thread which shows many different solutions to the problem.
Can't join Homegroup

This Homegroup check also has useful information to assist you in setting up your Homegroup.
http://helpdeskgeek.com/windows-7/wi...-to-homegroup/

This tutorial might also be useful.
Homegroup - Add Computer or Join