Unable to Share in a lil' network between XP, 2000 and 7...

Hi there people!

Well... I'm having a hard time sharing stuff between the folowing machines:
- A Windows 2000 desktop (yeah, I know, pretty old, but does it's work)
- My Windows 7 Home Premium desktop (has dual boot with XP Professional SP3)
- A Windows 7 Professional laptop.

Here what I did:
- Set names to each PC
- Set every PC to "HOME" work group
- Windows 7 PC's set on Work network
- All necessary services enabled (UPNP discovery, Server, device discovery, SSDP...)
- Windows Firewall enabled (Just in XP and 7 envionments, in 7 is a MUST since every time I configure something in the sharing and network center, it enables itself...)
- ESET Firewall disabled (just in Windows 7, XP and 2000 using ESET NOD32 2.7 which has no firewall)
- Disabled simple file sharing on XP

Now the problems as follow:
Whenever I try to acces 2000 machine from 7 machines, I get a "Unable to access resource" message... None of the 7 machines can see each other nor access shared stuff. Only XP is able to access shared resources from 7 machines (In this case, only my latop, since my other 7 instalation does dual boot with XP), cannot see it on the network... but acesing the route to the shared resource works...BUT 7 machine is not able to access XP resources... Obviously, 2000 and XP can share everithing without problems...

I don't know if this is clear... basically I have 3 pc's, but only XP and 2000 comunicate properly, 7 cannot access my 7 laptop and inverse, and only XP is able to access 7 shared stuff, but cannot see it on the network window...

I've read everything I saw here and over the net... but no results... I even do a format to my laptop (I anyway had to do it, Acer has a lot of software that is unusefull for me and just does the system unstable... now works better) and tried to share stuff without the AV software installed, but no result... the best I got was that each pc could see the other and themselves, but culdn't access shared stuff...

Something funny I noticed is that, I can see myself (In windows 7) sharing for example the "Shared" folder, but, when I try to access my own folder in the network window... I'm unable to see its contents (really funny taking in mind that that folder is stored in MY hard drive... is supposed to access it anyways...) In XP or 2000 you can see your own folders and access them from the network window... O_o

I also configured the security tab and the permissions... even setting to just "All" the users able to see the folder with read only permissions... the owner is me (Username = NAMEOFMYPC/FerchogtX) or I even changed that to "All" too... just XP and 2000 can share properly XD

Is there anything else I can do so I can share folders properly? specially between my 7 desktop and my 7 laptop (this last one using a wireless connection) and the AV software I'm using is ESET Smart Security 4 for my 7 instalations, and NOD32 2.7 for XP and 2000 ones.

I hope this is not too confusing... just tell me if it is... O_o

Thanks in advance guys.

See ya!!!

Already done... still unable to share I wanted to say "Everyone" instead of "All"... sorry, I got to translate into english because my versions of windws are in spanish XD

See ya!!