Thank you for your response Ivo.
The last lot of images I took of Comet Lovejoy, I did shoot in RAW and JPEG but still cant open them, nor the DSS image I had stacked a few days previous. No, still havent read the manual.
Have DL the other program which will not open the DSS I stacked, though will open the RAW.
I normally shoot jpeg, but occ do RAW, i just find jpeg easier to manage.