I shared a folder from the Shared Options of the folder allowing guest access. If I try to open this folder (or my Ubuntu system) from my Win7 system using the IP or the hostname, I get an error. But if I ping my Win7 ip from my Ubuntu and then try accessing Ubuntu IP over the network it suddenly starts working...but only for a short while or until the ping continues.
Note, however, that at this point opening my Ubuntu system using \\UbuntuSys from Win7 still doesn't work!
Why is this happening and how do I fix this?