Drive mapping problem windows 7 home edition

Dear Friends.
I am having windows 7 home edition 64 bit machine and windows Xp machine
Issue is I am trying to map the windows 7 Pc c drive in windows xp pc like \\vikram\c$ that???s make some minutes and it asks user name and password when I am enter the username & password that show the error message that is you might not have a permission to access the network drive.
how to solve …?
Please friends help me???