I had to do the complete system reinstall, followed with all Sims games reinstall.
Seems I got all my settings back as they used to be, except one: all my package files have the .package extension showing at the end of file's name, disregarding either I have disabled the "Hide extensions for known file types" or not. And it affects only the custom content package files, both Sims 2 and Sims 3 (ex. shasta_lethes-mesh-greenhousewindow_bottles.package - I want that package word not shown)

It's simply an annoyance, to have files' names to be shown longer than they are, especially for files with already long names

Did you have SimPE earlier, and didn't relinstall it? Could be your computer doesn't recognize .package files unless SimPE says they're SimPE package files. If the system doesn't recognize the file ending, it will sometimes show. Same with S3PE or TSRW or any other TS3 editing program that works with package files, if you had that installed.

There might also be some other setting that reset. Try here: http://windows.microsoft.com/en-us/...sions=windows-7

I'd recommend using the program called FileTypesMan to easily alter whether certain file types show their extension or not. You can also change a file extensions icon and the default command that happens when you click on it, which gives you further customization.

Associating the TS2 custom content files with SimPE helped! I haven't even thought of it before. Problem solved