I have tried the suggestions in another forum, but for me they have failed as a permanent solution.
Having successfully started up Win7 it is not there, however about five minutes later it appears.
A very small item that can be moved by the mouse see attachment 002.
Hovering over it it does not change.
Right and left clicks have no effect.
It is about the height and width of the Recycle icon.
Dark grey in colour, with what looks like a C half way down in white.

Try SlimDrivers and see if it picks up a driver update for your video card.

Wow, so I'm not the only one? It appears to be a Comodo artifact. If you have the Comodo firewall installed, right-click on the tray icon and turn on the "Widget" and you'll see that the residual item uses the same colors and font as the Widget.

You can move the artifact around the screen. If you turn off Comodo firewall, the artifact immediately disappears. I have yet to deduce what prompts it to appear. On my screen it always appears in the lower right corner just above the Windows Task Bar. But the timing of the artifact appears somewhat random.

Hmmm. I just realized I don't have the artifact now and it has been over six hours since I booted up. I *did* let Comodo install a program update earlier. Wonder if that fixed it?

Give that man a coconut.

It worked.

Updating Comodo has got rid of it.

Thank you a hundred times.

You're welcome. I only realized when typing the reply that I hadn't seen the artifact since updating. Four days later now, and definitely the Comodo update has taken care of it.