I have a Windows network, and mine went together seamlessly.
In Windows, you have to set up the network by naming it and setting permissions. For example, MSHOME is default. You then set up file and printer sharing, and then you can connect to any machine with those parameters. Macs don't need that, but you have to do that on your PC or it'll never work.
Also, check you firewall settings on the PC. Turn it completely off. Your router should have a better firewall anyway, and it takes out some steps.
From the Mac, if I want to connect to a Windows shared drive, you select "Connect to server" from the "Go" menu in Finder. Type in the IP of the computer you want to connect to, enter your password--and you only have to do that once--and bingo, there are your shares. Then you just click them and they "mount" like a drive.
If you want to manipulate files from one machine on another, get a VNC program. I have Chicken of the VNC on the Mac and Ultravnc on the PCs, and it works perfectly.
To make sure that your Mac is shared, highlight the drive or folder, select "get info" and make sure that the "shared folder" box is checked.