Win NT 4.9 Build 1.381 SP 4
I have lost the file associations for various bitmap formats (jpg, gif primarily) which were assigned tp PhotoShop - probably as a result of installing some other app. Now these files have no association and setting the association in Win Explorer doesn't seem to work. (There is no mime type in the properties).

Any ideas how to fix as it's a nuisance being without the quick view and the auto open of PhotoShop.