Why does my laptop computer keep freezing?

over the past few days my computer has been freezing up on me. i’ve checked the fans, its all clear of dust. i have done various virus scans and found nothing. is there anything i can do on my computer to help prevent this from happening. i’ve noticed it only does it at around the same time every night. i have an acer mini laptop if that helps with anything, any help would be extremely appreciated, thank you.