Everything goes rigrth until the moment I click on something for longer than 3 secons. WHen I do that, it somehow unclicks me and unselects the program (the window). Has anyone had this problem?
By the way I’m working on Windows 10 64bit
Hello simoncc, i’m new to this forum but have been using cubase since before 2000. I’ve not heard of this problem before which begs the question of what it is you are clicking and then holding which makes this happen. My guess would be either clicking on an audio file in the audio pool to listen to it or maybe writing a midi track so as to be ready for a final mix. Whatever the case more info is needed and in the mean time i shall try and replicate the problem you are having.
I have just recently upgraded to win 10 myself and wasn’t sure if cubase 5 would work. Well i can tell you i checked with microsoft before hand and they confirmed that the program was compatable. Anyway i can play, record, record and playback audio at the same time without any crackle hiss or pop in pure clarity. As you have just upgraded you might have to update your drivers for cubase and possibly your graphics card and the same for other programs if they are not working. 
I’ll try to update my drivers. In fact, windows has just updated, I’ll tell you how it goes