Hello, Jessica! I'm from Brazil, so pardon me if you don't understand everything I will write down here!!!! I think I could help you by overviewing your HijackThis log, but first I should warn you that this is not everything that have to be done, since it won't show many of the issues with your computer, like services and other ways to start a (malicious) program. You also should take a look at Windows\System32 (syswow64) folder, and always be aware of what files are being stored there (I suppose you are running Windows. It would be useful to know what version, like XP, Vista or 7, 32 or 64 bits). In spite of doing anything, you should download, install and run MALWAREBYTES ANTIMALWARE, and try to change your antivirus program. For example, if your computer is running Avast, try to change to Avira or some other free program, just to try to remove the installed malware in the computer. Well, depending on the level of infections, it is indeed the best choice to reinstall everything, since the time you spend looking for intruders isn't worth, and you cannot be sure that everything will be fixed! But, let us know what HijackThis will show! Regards!