Two more suggestions for long term:
- try and get hold of a third machine and see if you can get it working with either of your laptop/desktop. It should clarify where the problem lies (outgoing from the laptop or incoming to the desktop).
- If you can establish which machine has a fault, treat yourself to an upgraded hard drive for it and re-load windows from scratch onto a new drive. Before you add any extra software, try to get the network up and running.
If it works you solve the problem, go on to re-install your old software and files, you can trash the old hard drive. If it doesn't, at least you have a new hard drive which is usually useful. Most laptops which have device bays can have a second hard drive in the bay, fabulous for really secure backups. Desktops always need more storage.
BW