Which version are you on?
If it's a CC version, try this... Import any file that you want to put into a sequence, then drag it over the 'New Item' icon in the lower right of the project panel and it should auto-create a new sequence for you with settings that match the source file. Also, in newer versions, there is a dummy sequence present with a text string in the middle of it that says 'drag media here to create sequences' so try that as well.
Thanks for the answer. I'm on CS6. The drag&drop doesn't work, well it seems as it would work if the other options of creating a sequence would work. Therefore I think, the error must be a level beneath that stage. But I actually already reinstalled Premiere (just Premiere, not the whole Suite, but that would be the next step) and it still doesn't work...
Hard to say, it sounds like something is corrupted with your project. Can you try it with a new project? Also try deleting the app preferences.
As i haven't started working, I can start new projects as many as I wish, and I did this a couple of times. I deleted the old projects. Today I first uninstalled Premiere and installed it from scratch. It then worked in the beginning but after a restart of the project, again, it didn't work. Where can I delete the app preferences?
Deleting Preferences: hold down ALT while restarting Premiere.
If you also hold down SHIFT it resets Plugin cache.
Nope, still doesn't work... It just doesn't react when opening a sequence... Normally it should ask directly when opening a new project, shouldn't it?
AMD R7 265M
Aight I got it. I had to delete the data within "AppData>Premiere Pro" in order to get the sequences done:)