Can't connect to share file from my windows XP after upgrade to Yosemite

I have set up file sharing between my iMac & windows XP, it was working fine before. After I upgrade to Yosemite, I can't access the file from my XP to iMac ! But it is ok from my iMac to XP. I have share folder on both machines share it to each other. I am using workgroup network "Mshome", no domain. In my XP I can see the iMac computer on my network, but overtime I check on it it prompt username & password. I try enter the username & password of my iMac account it won't work. Since Yosemite now don't have short username anymore. I even create a new account name to try but still not able to connect.

The previous set up I have the same account name & password for both iMac & XP, it will connect directly when I turn on the machines.

I do remember when I first setting up it, on my XP username login I need to put some different with the username, but I didn't write it down or record it. Can anyone tell me how to I connect again to my iMac ?

Thanks for you help!