Dennis has an older Windows XP machine with two drives - one for programs, one for data. Lately, Malware Bytes has been finding "suspicious files." Could they be malware? He quarantined the files and now he can't access his data. When he unquarantined them, they were deleted. Leo says it could be a false positive.
Malware Bytes is not an anti virus utility. Once he quarantines something, he can't use it again. Going to system restore really isn't reliable since malware will delete the restore points. Leo advises pulling the drive out of the computer and have an expert get the data off it. Or he could get a USB interface for it and then plug it back in via USB to get the data off. It's so bad that Dennis really needs to start over. While he's at it, he should rebuild the machine and upgrade it.