Due to corrupted installations or newer program releases, reinstalling your ESET security product is sometimes necessary.

Uninstall

1. Click Start → All Programs → ESET → Uninstall. After you uninstall, you will need to restart your computer.
   

   

   
   Warning: Do not attempt to uninstall your ESET security product using the Windows Add or Remove Programs utility from the Control Panel.
    

2. After restarting, confirm that you can see hidden files and folders by clicking Start → Control Panel → Folder Options → View and select the Show hidden files and folders option.
    
3. Click Start → My Computer and then navigate to and delete the following folders:
   
   C:\Program Files\ESET
   C:\Documents and Settings\All Users\Application Data\ESET
   C:\Documents and Settings\%USER%\Application Data\ESET
   
   Windows Vista and Windows 7 Users must delete the following folders:
   
   C:\Program Files\ESET
   C:\Program Data\ESET

Re-install

1. Download your ESET security product using one of the links below for Windows NT/2000/XP/2003/Vista/7.
   
   You will need your unique username and password to download your ESET security product. Please reference your confirmation email for this information or click here to retrieve your username and password.
   

   

   
   Important! Please check your operating system version before downloading.
    

   32-bit:

   ESET Smart Security 4.0: http://download.eset.com/download/win/ess/ess_nt32_enu.msi
   ESET NOD32 Antivirus 4.0: http://download.eset.com/download/win/eav/eav_nt32_enu.msi

   64-bit:

   ESET Smart Security 4.0: http://download.eset.com/download/win/ess/ess_nt64_enu.msi
   ESET NOD32 Antivirus 4.0: http://download.eset.com/download/win/eav/eav_nt64_enu.msi
    

2. When prompted, select Save and save the file to your Desktop. Once the download has completed, click Run if you are prompted. If not, navigate to your Desktop or wherever you saved the ndntenst.exe file and double-click it to open.
    
3. Follow the instructions in the ESET Installation Wizard to install your ESET security product.
   

   

   
   NOTE: For more detailed installation instructions, please click here for ESET Smart Security 4.0 or click here ESET NOD32 Antivirus 4.0.
   

Related:

How do I uninstall or re-install ESET Smart Security/ESET NOD32 Antivirus? (3.0)

How do I manually uninstall my ESET security product? (4.0)