User showed me this clock on the screen today - its modal but fixed on top. Anti-virus revealed nothing - and no shifty programs or services to my eye are running.
Hopefully AV deep scan will reveal something?
Download Process Explorer from http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx
& then use the 'Find Window's Process' Tool to find what process is running it. You can then google for the process to find if it might be a virus or a prank.
Thank you for your interest in this question.
Because it has attracted low-quality answers, posting an answer now requires 10 reputation on this site.
Would you like to answer one of these unanswered questions instead?