Ever since I upgraded my iMac to OSX Lion my windows 7 based pc is giving me problems when i try to access my mac files on it.

The mac appears underneath the network category but when I click it I am getting an access denied, need network username and password. Well whenever I type the info in I am getting a log in failure.

Thing is I never had to do any of this when using Snow Leopard. So far I haven't changed any of the setting on the mac. I would like some help.