Vista is asking for username and Password

[H@rsh]

Hi Guys,
I have a Windows Vista laptop and 2 Windows XP machine(SP2) at my place...I have connected them with the help of a Switch...The problem is that when windows vista try to access any shared folder shared by XP machines,then a prompt with username and password pops out...
Vista is able to detect the machines in Network Map but is not able to access the files..XP machines can access shared folders shared by Laptop and that too without password....I have changed the permissions of sharing to co-owner while sharing and configure the firewall also but still it is prompting for username and password which i have never set(there is no password on XP machines either)...Please help...

[Polkadot]

While running your Vista machine and trying to access shared files on the XP machine(s), when it asks for ~username~, enter your XP username. When it asks for password, since you have none set on the XPs, just hit <ENTER>.

[smalldog]

When you login to windows any passwords needed or login windows automatically without password?If login automatically you don't need password to access if not you must enter pass that's security normally in windows. Just enter password for user using on windows that you want access!

[Raymond]

You have to enable file sharing in XP or else you'll be getting the login prompt.
Follow the steps provided at this page.
http://www.practicallynetworked.com/sharing/xp/filesharing.htm

[H@rsh]

Thanks for the replies but still the problem persists..
I have already enabled the file sharing(simple) in Windows XP..
@smalldog
I have not set any passwords on XP machine...It just load in automatically...
@Polkadot
I have to enter both 'username' and 'password' and then only it allows me to login...Otherwise it prompts me to enter the password if i only enter username..