>So, what exactly should be my steps? It's very unpleasant feeling - feel stupid facing your own computer... :(
Managing file associations (e.g., DOC is associated to MS-Word) through Windows Explorer is a complicated task.
Get the freeware I suggested (Freedom of Association), and delete the offending association. Then, double-click on the JPG. Windows should ask you with what program you want to open it. Next time, it knows (if you marked "always open with this program").
HTH, Hilmar.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)