File share permission problme in server 2003

Hello,
wish to grant full permissions to each user on the network to read, write, change, ect.
before used the server we used the local windows xp network then i got a file permission problem when i up the own windows server 2003. my user not able to modify the file of my old and current file which i shift form my local network.now i am using the active directory service.
Somehow, while experementing with settings, I made some changes and now some folders and other documents within folders are not all accessable from every client (all Windows XP proffeshional edition). I can not figure out what the dependent variable is that makes some files accessable and others not. While perhaps I have about 300000 file folders on the server, and document files within each. I wonder if it is either an ownership problem, or one having to do with different original authors of the files/documents. I say this because some documents within the same folder are accessable and others are not.

I have tried to set the security and sharing permissions so that "administrators," "all users," " everyone" and each individual user all have full permissions. Yet some files and documents are still inaccessable.

I just wish to make all files and documents available to every user on the network.And they will read, modify and delete the file from my server.

Pls give me the right solushion

wating for u

Configuration: Windows XP
Internet Explorer 7.0