Have you tried to include the protocol http://
Did you try
http://www....
Try this: Tools > Internet Options > Advanced > Browsing
Uncheck the Enable 3rd party browser extensions
If this clears your problem then find out who the culprit is with this tool.
AD-Aware Scan your system for advertising Spyware
This free utility scans your memory, hard drives, and your Registry for
references to ad-related servers from Web3000, Gator, Cydoor,
Radiate/Aureate, Flyswat, Conducent/TimeSink, and CometCursor, Webhancer,
DSSAgent and Alexa.
http://www.lavasoftusa.com