Vista - access denied to host pc for file sharing

I am having an issue with accessing the host pc. I have shared a couple of folders on the host pc but when i try to access it from two other pc in our office i get an error of access denied.

from the host pc i can access the files shared on the other two pc's. From pc 1 i can access the files on pc 2 and the same goes for pc 2 accessing pc 1 fils with no problem. ITs just when i try and access the host pc from pc 1 or pc 2 i can and i get the error saying access is denied.

I have went onto the host pc and took off the firewall and also deleted the McAffee secuirty software and also when in and made sure the settings are on for file shairing but still nothing. Can some one help me please.

Thanks.

Do you have any passwords set up that aren't allowing access, are all machines in the same workgroup. How are the machines connected, wired or wireless and is there a router in the mix ?

Just throwing out ideas for you to check

I am not sure about the passwords. All of the PC have there own user set up and passwords.
Yes the machines are on the same workgroup and they are wired. there maybe one wireless laptop down the road. Yesthere is a router and a switch. I have all the pc going right into the wireless routers.