I have a PC, not in domain. It is in network through NIC to other computers.

It had 2 OS installed. Windows XP and Windows Vista. Some days earlier XP didn't work, it said "Reinstall the hal.dll file."I am working on this.Currently, this is not the issue. I am using Vista now. Vista works fine.

The problem is that from Vista, i cannot connect to other computers in the network when i try to connect from "RUN"(By typing IP in the run like \\192.168.1.170).The username and password asking dialog box prompts, but doesn't let me access the computer. But i can use the other computer by using Remote Desktop. The same user name and password works with Remote Desktop.What may be the cause ?

The vista operating system does not like sharing. you will probably have to change the permissions in order to share/access the other computers.

Note...
when you use different operating systems on the same machine...it is the same as having totally different computers....each operating system has to be set up as its own within the network/sharing

I got ur point. How can i change the sharing properties in Vista ? Any idea ?

try this first:

start > r. clk. "My Computer" > explore and choose "C" drive or what ever it is named in your system.

R.clk. "C" and choose properties. In the properties box >sharing tab> check to allow sharing. apply and exit to reboot.

I understood ur point. But the sharing button is disabled in the sharing tab of the system drive. In my case Vista is installed in drive D: and sharing button is disabled in the properties.

Read this article for a better understanding and how to configure sharing in windows vista!

File and Printer Sharing in Windows Vista