Hi, Is there any anti virus I can install on my external Hard disk 1tb My book, to avoid any virus attack while copying any file to it. Thank you

Most Windows programs allow you to install them anywhere, but they'll still need to have access to the registry (almost always on the "C" drive). Were you to unplug the drive, the program would stop working (and may even cause further problems). It's lways best to allow the defaults when installing most software (usually "C:\Program Files\xxxxx" where xxxxx is the program's main directory). And any decent anti-virus program would monitor files you move from drive to drive anyway...

before unplugging the drive, please stop he antivirus... BTW, you can install any antivirus for such purpose