ESET Uninstaller is a free tool for removing ESET security applications which can't be uninstalled in other ways.
Fully uninstalling antivirus packages isn't easy, especially if they're damaged, so it's best to try the regular uninstaller first. Try it once; if there's a problem, reboot and try it again, immediately; maybe reboot into Safe Mode and try it again. Or reinstall the entire program over the existing installation, if that's allowed, to try and fix it.
If all that fails, ESET Uninstaller may be able to help. It's tiny - under 1MB - and fortunately doesn't need installing itself, so just download the program, reboot into Safe Mode and run it right away.
ESET Uninstaller opens in a console window, but normally it's still extremely easy to use. Read the warning; press "Y" to confirm you'd like to continue; read the list of ESET products installed on your system; enter the number of the product you'd like to remove, then wait as it's wiped.
If ESET Uninstaller doesn't detect your ESET product then it might be necessary to use a command line switch. Run ESETUninstaller.exe /help or check ESET's Knowledgebase article for more information.
If your ESET product is broken and can't be removed then ESET Uninstaller should be able to help.