You may have a virus. Assuming so - See if you have any
files in the C:\Windows\System32\Wins folder and if so,
they may have been "dropped" there and could be malware.
Immediately after login go to Start, Run, and
type "Shutdown -a", Enable your firewall client, go to
Windows update and install all updates. On reboot start
in SafeMode and delete the files from the above folder.
Reboot again and check to see if they exist.
Future:
1. Get an anti-virus program.
2. Turn on your firewall client.
3. Update your system regularly - Windows, Office,
Anti-Ad definitions, and Anti-Virus definitions.
4. Get a good anti-ad software and run-it regularly -
suggest at least AdAware from LavaSoftUsa.com.
5. Use passwords on all of your accounts (at least 7
characters of which at least two are not letters, and
place the non-letter characters after the 3rd position of
the password.
6. Don't download and install anything from a fly-by-
night software company.
7. Don't open email attachments from anyone you do not
know.
If everyone followed this advice, at least half of these
postings would disappear.
This is all based on the assumption that you have a
virus/trojan/dropper. If you don't - sorry. The list is
still valid in any case.