Thanks for the suggestions, but still have the issue with the icon in bottom right if the thumbnail. The thumbnail itself is always fine, it's just the icon! If I change view to small icons they all look ok but then I go back to large icons and the mini icons are still the problem. It's even doing it on word docs/excel/PDF files occasionally too. If I logout and login it fixes, and if I go to default program's and set the associated program for a vid file to media player again it also fixes everything. But the issue always comes back. I believe I know what is triggering it too. All remains fine until I go into my add / remove program's list (detail view). This obviously sets something off as then I will go into the videos or documents folder and see the thumbnail cover/display icon become random again. The random icons are always icons relating to other programs on my laptop. And the same random icon will be used for all file formats. For instance all video files will still display the thumbnail but in the bottom right the cover icon might be a control panel icon for all videos, whilst all word docs showing a thumbnail view might have another consistent although random icon. I do have a good 40 gigs worth of video and hundreds of photos but I can't say I really noticed this issue until recently. Although I don't go into add/remove programs list regulary. But now I know it's happening it's frustrating. Any ideas?
I have attached a Jpeg example, as you can see in the bottom right corner the icon relates to Google Earth icon, but these are video files and should have the orange media player mini icon.