Windows has a complicated series of steps to open a link online. Leo also suspects that Malware is likely the issue and recommends using the Microsoft Malicious Software Removal Tool (Click Start, Run, and type "MRT") and then choose the thorough scan. He can also try MalwareBytes.org. If that comes up clean, and he has up-to-date antivirus, then the File Association Database may be corrupted. Fixing it is problematic and time consuming. It may be easier to backup his data, wipe the drive, and start over.