The best method Jose could use to keep his computer safe from malware, in addition to avoiding suspicious email attachments and clicking on pop-up ads, is to install an antivirus program. This will help detect and prevent malware infections on his computer.
The other options, while they may have their own benefits, do not directly contribute to malware prevention. Clearing search history and avoiding social media are not effective methods for preventing malware, and keeping the computer fully charged does not impact its security.