The reason I say 'after the login screen appears' is that sometimes, when I switch on the computer and come back a couple of minutes later to log in, I don't notice any freezes once my account loads. When I arrive at just the right time, however, I can't log in because the system is busy freezing.
I'm pretty sure this behavior can't be blamed on my virus scanner doing some sort of boot scan, so I would like to hear any ideas about a possible cause or even solution. Thanks in advance!