In76 Smudge / Murky Blur please help!!!

[dreamstationx]

Hi Chapps..
I have an In76 which is excellent however I turned it on the other day and on the white blank screen where is searches for inputs I noticed in the bottom right a smudge or blur type mark.. It looks like its an out-of-focus reflection like the light is shinning through something glass.... It s a murky purple / blue colour and although light and hardly noticable on films, its there and visible on bright white scenecs and my xbox360 dashboard. It about the size of my hand.

I have cleaned the lense using all sorts bt nothing... if I move the projector the belmish moves so I know its coming from the unit, its not on the screen itself....

Any suggestions..??? Is it inside..?? dust or dried condensation..???

I know the night before I had my window open for an hour or so blowing cold air in and the projector is sat on the window ledge... other than that, cant think of anything... Please help!!