virtdetect: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/virtdetect - from package: virtdetect

You may install the required package with command yum install {package}

Error in other languages:
virtdetect: bevel nie gevind nie
virtdetect: comandă negăsită
virtdetect: comando não encontrado
virtdetect: commande introuvable
virtdetect: command not found
virtdetect: käsku ei ole
virtdetect: không tìm thấy lệnh
virtdetect: komanda nerasta
virtdetect: Kommando nicht gefunden.
virtdetect: kommandot finns inte
virtdetect: komut yok
virtdetect: nie znaleziono polecenia
virtdetect: níor aimsíodh an t-ordú
virtdetect: no se encontró la orden
virtdetect: no s'ha trobat l'ordre
virtdetect: opdracht niet gevonden
virtdetect: parancs nem található
virtdetect: perintah tidak ditemukan
virtdetect: príkaz nenájdený
virtdetect: příkaz nenalezen
virtdetect: команда не найдена
virtdetect: командата не е открита
virtdetect: 命令找不到
virtdetect: コマンドが見つかりません