AboutCarolyn Meinel Expertise I cover Windows, Unix, TCP/IP and Ethernet security questions. I do not cover Mac, Palm Pilot, or other networking issues.
Experience Books by Carolyn Meinel: wrote a chapter for The Hacking of America book (see http://www.amazon.com/exec/obidos/ASIN/1567204600/happyhacker)
My article Code Red for the Web for Scientific American was reprinted in the book Best American Science Writing 2002 (see http://www.amazon.com/exec/obidos/ASIN/0060936509/happyhacker). My book The Happy Hacker: A Guide to Mostly Harmless Hacking is now in 4th edition with a Japanese edition (see http://happyhacker.org/hhbook/).
Question i have deleted winupdate.exe file is it a important file? if yes what i do?
Answer You were right to delete that program as it is used by a dangerous Trojan.
Did you delete this file because your antivirus program found it and asked permission to delete it? If so, then your antivirus program probably took care of any problems created by this Trojan. However, if you aren't running an antivirus program, I suggest that you immediately install one. You can get free trials of two of the best Internet security programs, Kapersky Internet Security, which offers a free 30 day trial at http://kapersky.com, or F-Secure's Complete Internet security suite, which offers a free thirty day trial: https://store.f-secure.com/cgi-bin/dlreg/ml=EN?ID=FSISTB&desid=TRIAL
