Recent viruses use admin shares to infiltrate your system, to disable them:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\LanmanServer\Parameters
Create new DWORD value called AutoShareWks (AutoShareServer on servers) and set it to zero. Once completed, type "net share" at a command prompt, it should return the following:
C:\Windows\system32>net share
Share name Resource Remark
-------------------------------------------------------------------------------
IPC$ Remote IPC
The command completed successfully.
C:\Windows\system32>
Administrative Shares