Open up notepad, paste code below and save with VBS extension, now run.
sNewName = "put new name here"
Set oShell = CreateObject ("WSCript.shell" )
sCCS = "HKLM\SYSTEM\CurrentControlSet\"
sTcpipParamsRegPath = sCCS & "Services\Tcpip\Parameters\"
sCompNameRegPath = sCCS & "Control\ComputerName\"
With oShell
.RegDelete sTcpipParamsRegPath & "Hostname"
.RegDelete sTcpipParamsRegPath & "NV Hostname"
.RegWrite sCompNameRegPath & "ComputerName\ComputerName", sNewName
.RegWrite sCompNameRegPath & "ActiveComputerName\ComputerName", sNewName
.RegWrite sTcpipParamsRegPath & "Hostname", sNewName
.RegWrite sTcpipParamsRegPath & "NV Hostname", sNewName
End With ' oShell
MsgBox "Computer name changed, please reboot your computer"