Computers can no longer see eachother & share resources

Question

I have the wireless WRT54G2 router. I connect using my laptop wirelessly through the router. My desktop computer is connected through the router wired.
Laptop is Vista, desktop is XP. This is nothing new, and everything worked fine up until a few weeks ago. I was having connectivity issues and so I was trying all kinds of things to see if it would fix it, including power cycling my cable modem and (possibly my router as well.. this being a few weeks ago I don't remember). Finally I got my connection back up and running, and I remember noticing a message had popped up on the laptop (I think it was above the system tray in the same style with which the messages saying you're connected to the internet pop up) that said something about my ip address. I think this is the key to the problem. I wish I could remember exactly what it said. But it went away by itself, and I was able to access the internet just fine from both computers, so I thought nothing of it. (I should have known better.)
Today for the first time since that incident, I was trying to print something from the laptop using the printer that's connected to the desktop and is shared over the network, and realized I couldn't. Upon investigation I realized that now, I can't see my desktop at all under view computers and devices (keep in mind, I was always able to prior to the earlier incident). Being Vista, I figured there was some setting that got switched without my knowledge or something... and it wasn't that either. My network is still set as a private network with network discovery turned on. No firewalls got turned on. Checked my desktop's settings, nothing changed there that I can find, either.
I have been trying unsuccessfully to find a solution. My router's SSID matches the connection my laptop is connected to. The two computers have unique names with the same workgroup.  They just cannot see eachother anymore.
I also noticed when i'm looking at the settings for my router under "Wi-Fi Protected Setup", it says it can't find my client device. After reaching 99% it says "Connection Failure! Your client device failed to connect to the network. Refer back to your client device for further instructions." I have noticed that the light over the button is sometimes steady green and sometimes is steady amber. I don't recall seeing it amber ever in the past. I don't know if this is relevant or not, just trying to include all the information I can. Can anyone else give me some clues? Thanks.

Answer 1

I finally found the solution to my problem, if the ping works of course, then it is probably the same NetBIOS problem I was having. Here is the solution:
On the VISTA Machine:
1.  Right click your adapter in the task bar at the bottom left
2. Select  "Network and Sharing Center"
3.  On the left side, click "Manage Network Connections"
4. Right click on the adapter you are using to connect to the network.
5. Select "Properties"
6. Highlight "Internet Protocol Version 4 (TCP/IPv4)
7. Click the button "Properties"
8. Click the "Advanced" button
9. Click on the "WINS" tab
10. Under the section "NetBIOS Settings", select "Enable NetBIOS over TCP/IP
11. Click "Ok" on all configuration boxes to save settings.
On the XP Machine:
1. Open Control Panel 
2. Double click Network connections
3. Follow steps 4-11 from above
Hope this helps
Jon