I'm not able to access drive C from network like in XP using command RUN>"\\ipAddress\c$"

even after givin right password, Password prompt reappear instd of opening network share, can any one tell me why?
I've installed my Vista home Premimum edition week ago and very least chances to get affected by virus.

By defauly hidden administrative share is disabled in Vista due to security reason, you need to follow the below four simple steps to enable it first:

1. launch run and type in regedit
2. Once you are inside the registry just go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ Windows\CurrentVersion\Policies\Syste
3. Right click anywhere on blank space and create a New DWORD 32-bit or DWORD 64-bit(for VistaX64)
4. Name it "LocalAccountTokenFilterPolicy" and finally change its value to 1

now you'll be able to access all hidden administrative share

Thanks bro!