Windows Network problems

So...i have a network here at home, with 3 computers, and then suddenly, the computer my dad uses isn't visible in "network neighbourhood" alongwith the others, but i can still ping it, and i cant still access the other computers from it, and the internet still works, but it just doesnt show up...so i cant browse files which are shared on it from the other two computers.
but no big deal, i dont really use that computer, only as last minute backup, so i leave it alone.

Now, suddenly, the same thing happend to my main computer, and this is where it gets annoying, i tend to do lots of networking stuff, moving files and so on...so i need them to be accessable...but it suddenly dissappeared, poof, just like that, from one minute to the other.
The same thing happend to my file server, but it cam back within a minute.

Now this is really freaky, there are no firewalls on here or anthing to block connections, doesn anyone know how to fix this?
And no, using linux/mac is not an option.

Yeah, I had that problem for about 5 years of home networking with Windows. Never figured it out. Windows is teh sucky network OS.

Run the network setup wizards again on all machines.

Worked like a charm with my windows boxes.

Ok, but what makes it go boom? no one knows the reason? or should i just throw it in the "windows sucks" pile?

Throw it in the windows sucks pile.