Does my computer really have a virus?

So, last night, my Windows Defender turned on and said I have spyware, trojans, etc, etc, and it would not stop advertising this, and the only way to get rid of the aforementioned was to upgrade my defender for a minimal fee of $50 for a 6 month subscription. On my guest account, however, the computer functions properly, but on my own account, Defender goes crazy, slows down my programs because they are “infected” and it’s driving me nuts because I’m not really that great with this kind of stuff, so how do I find out if it’s really a virus on my computer(I have used several programs to scan my computer for all the virus and trojans and none of them have found anything save for Defender) or if Windows Defender is just trying to pressure me into an update?