Thanx very much for the information.
I scan the PC with Noadware as you suggested and a malware with the name W32.HLLW.Gaobot.CA found and located at registry:HKLM\system\CurrentControlSet\Services\nm. I found default as the registry entry. So I deleted the folder nm. I also downloaded registry entries that enable task manager and restored folder option from
For the network issue, I have downloaded the information from microsoft for study and applicaton. Its been a wonderful experience. Happy and Prosperous New year to you and crue.