what's with file sharing?

I was helping someone set up their new mac notebook running OS X 10.5 with all current updates and I absolutely could not get file sharing to work. I did turn it on under sharing and told it to use SMB but even after that and restarting, it won't list SMB as a service under that one directory utility in the utilities folder. So I couldn't change the workgroup so instead I changed all the PCs to "WORKGROUP" instead of "MSHOME." Well apparently SMB is running cuz I can at least see the mac from the PC but as soon as I try to open one of the shared folders (the drop box) from the PC it tells me I can't access it cuz I don't have permission or something like that. So I figured, whatever, I'll go on the mac and try to just grab the couple files I want to transfer off the PC and onto the mac. As soon as I try to open a server connection to the PC, which it can at least see, it asks for a username and password. The mac username was in there already so I put the mac's password in too and it rejected that. So I put the account name of the PC user that I was currently logged in as and left password blank since they don't have one and that didn't work. So I added a password to their account on the PC and then put that password in and still nothing. When that didn't work, I found myself wondering "what the HECK is it even asking for a username and password for? I don't have some fancy corporate network with domains and complicated permissions and stuff!" I had wide open sharing preferences set on the PC and I've done this so many times, I know another PC would be able to pick up the shared folders and access the files just fine with those settings. So what exactly is preventing it from working in each direction? And what username and password is it asking for?

I had issues with this today as well my pc can see my mac but my mac can't see the PC. I can transfer files into the shared folder using the PC but not the MacBook.

Make sure you have turned simple file sharing off on windows, it caused loads of problems for me.

service pack 3 on the xp side will cause loads of problem also.

Well according to microsoft on XP Home you can't turn off simple file sharing cuz that's all it uses Also, it may have SP3 I did see some pending updates but didn't look which they were so maybe they don't. I don't really feel like uninstalling that if they do. I really hope the mac recognizes my hard drive enclosure or I'm gonna be very unhappy cuz I doubt I'll ever get file sharing working