The best thing to do is first backup all of your personal files, reformat the drive and reload a fresh operating system.
Use a professional all in one antivirus, not the type that is downloaded free from the internet.
After loading a fresh OS, and a fresh professional antivirus, scan your backed up files before loading them into the fixed hard drive.
certain types of software, which you loaded, prevents deletion, and there is little hope of getting rid of it until you wipe the drive entirely. In the future, avoid free downloads, and use only real professional programs that have been signed by the OS manufacturer.