Faulty Network!

Hi all, hope you can help.
Desktop: Gigabyte GA-870A-UD3. AMD Phenom II X4 B60. Corsair (4x2 GB) 1333C9 DDR3.
SATA II Seagate ST31000520AS 1TB. SSD 32 GB.Cache drive: Sandisk SDSSDRc032G.
LiteOn iHAS124 B DVDRW. NAS: Zyxel NSA 310 Seagate 2TB. Laptop: HP Pavilion Dv7 320 GB spinner.
Both computers running Win7/64 bit Home Premium.
Router: BT FTTC Modem and TP-Link WR1043ND 10/100/1000. Bit Defender Total Security 2014.
Both computers and the NAS are separately running fine, currently wired, although the laptop is wireless-enabled and sometimes used as such.
PROBLEM: Cannot set up Homegroup or Network correctly. All devices appear on both desktop and Laptop, but cannot access laptop from desktop and vice-versa. Can access NAS from desktop, all files & folders accessible, but not from laptop. Start setting up Homegroup from laptop, take password to desktop, receive message “You cannot set up a Homegroup on this computer”
ACTIONS: I have set Bitdefender Firewall Adapter settings to 'Add Zones' for all devices, by IP's. I have set Windows Firewall to allow Permissions for sharing. I had reinstalled Windows on the laptop, which was previously running under another name. I have had to delete this name in the Registry, and the laptop has a new name, as my wife is now the User and has her own UAC. I have used Services under Computer Management, to set up all appropriate Network Services.
I would appreciate advice at this point, I am lost! How can I retrieve my Network? Do I have to take down the Network and start again, and if so, how do I do that please? Images of desktop and laptop are saved on the NAS, with all music, photos and videos.
Thanks for any advice!

Hi from sevenforums,
Your NAS isn't included in the homegroup. Your NAS can be the file sharer as it is.

To setup homegroup chose the laptop and join using the desktop.

Leave the Homegroup:
Leave a homegroup

Set on all computer to Home Networks see below:
Choosing a network location - Microsoft Windows Help

Create a homegroup on laptop:
HomeGroup from start to finish - Microsoft Windows Help

Thank you, Cyberman and I apologise for not responding sooner. I have copied & printed the information you gave and am working on it, will get back to you as soon as I can.

Much obliged for your help.

I have been visited by my network engineer grandson, fortunately for me having a few days holiday, who has set up the network without using Homegroup. He also found several laptop drivers missing and/or out of date, so fixed that for me too. He left to visit his cousin, who is also having computer problems. We are lucky to have such a family member, but we all try not to bother him unnecessarily.

Only respond when you have time, try to help out where I can mate and a network engineer is handy mate.