Good advice so far but this hasn’t been mentioned yet - it could be a slow network link that hangs explorer while it gets a response from the server - do you have any network drives or shares active?
If not, consider turning file and printer sharing off so it’s not actively searching out network devices and shares every time you open a new file explorer instance.
The scammers are spamming her inbox with junk in order to hide the legitimate email (the laptop receipt that you found).
She needs to contact her bank’s fraud department and report this. Cancel the compromised card and get a new one. Also go through all the spam to find any other legitimate emails (i.e. anything with her payment details), and act on them accordingly (i.e. cancel order, refund, etc.).
Looks like her card details were compromised and the spammers are trying to get away with making a few big ticket purchases without her noticing til it’s too late. It’s unlikely that her email account is also compromised, otherwise they wouldn’t be so worried about burying the purchases they’re making under a mountain of irrelevant spam.