Inactive email disappeared

[Inactive] email disappeared

My elderly mother-in-law once again has a problem with her computer. She said about two weeks ago her email disappeared. She showed it to me tonight when I picked her up to take her to our house for dinner. She's running Windows Vista and using Windows Mail. All of her mail folders show empty. I tried sending her an email and nothing happened. I opened up Internet Explorer and her home page was changed, which is why I am posting in this Malware forum. I opened Internet Accounts and nothing appeared to be there. I took photos of the various windows mentioned above with my phone and emailed them to my computer. If there is a way to do so I could post them here as well.
Any advice will be appreciated.

 

I checked and made sure her firewall is turned on. I ran a full system virus scan and no threats were detected. I contacted her ISP and verified that her email account was still active. They helped me set the email up on her computer again. It downloaded about 200 messages. I sucessfully sent an email to myself. I ran out of time to do anything else since I had to go to work. I'll try to get over to her house in the next few days to run the Malwarebytes and DDS scans.