Vista - Not able to access my own local public folder or share printers

I have an issue where i cannot access my own public folder through the network folder. I have internet access on my desktop and have a direct wired connection to my router. I also have a couple of laptops accessing the current network via wireless and they all have internet. The problem is that those other computers dont always show up in the network folder on my desktop and they dont have access to the printer (sometimes a friend has a laptop over and i can see that one). I thought it was an issue with the laptops but my PC (connected to the printer) cant even see its own public folder... so i am assuming that isn't right. One other thing - the laptops can all see my desktop with the printer on it but cannot "find" the computer when i click on it (network sharing is all turned on with no passwords and private style network).

Any ideas? A few months ago i changed routers and since then have had an issue with printer access but no problems with internet access... dont see anything in the router settings that is obviously wrong...

Thanks