On all of the source inputs there is flickering on the right top side. It looks like a stobe or flash. If I turn of the tv and back on then it stops. Sometimes it will stop on its own also. When on a blank source it is visible also.
The unit will be 2 yrs old this christmas.
What can the problem be ?

Try turning off the TV and then unplugging it for 20 minutes then plug it back in.
This may sound like a strange procedure however it has resolved similiar problems for others.

Try other source inputs. If you see it on all of them, it's likely a) ballast, or b) lamp.