Was my computer hacked? 2 questions

So, when I got back today from class and tried to access my laptop, my computer just wouldn't take my password. I don't know why. I tried everything. I used my old passwords. I made sure my caps wearn't on. EVERYTHING, but nothing worked. I don't think I put my password in wrong. I usually don't have to think about my password. I just put it in. Anyways, I took my laptop to my campus's ResNet so they could get it to work. One of the guys put a flash drive into my computer so I could reset my computer's password. This worked. They ran my computer and there was a virus on my computer, which doesn't make sense because I have a 2-year subscription to Webroot SecureAnywhere. I haven't downloaded or been on any dangerous sites. I've done COUNTLESS scans. I'm thinking this might be related to my roommate. He brought a router for our room and had to put his password into my computer so I could connect to his router. Could he've hacked my computer through this? Lastly, is it possible for my computer to be damaged from having the people at ResNet having to reset my computer's password. They told that I might've lost some data when they did all this. Is it possible for any future downloads to be messed up?

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