Ehhh....
Now I have another question..
I want to check several PC's and created a checkbox for every PC.
But only one is checked while I'm sure (Dosbox ping)that both PC are powered on..What am I doing wrong ?
Code:

$CheckPCk1 = $Form.Controls.CheckBox()
$CheckPCk1.BackColor = 212,208,200
$CheckPCk1.CheckAlign = 16
$CheckPCk1.CheckState = 0
$CheckPCk1.FontSize = 8,25
$CheckPCk1.Height = 21
$CheckPCk1.Left = 105
$CheckPCk1.Text = "testpc"
$CheckPCk1.Top = 105
$CheckPCk1.Width = 50

$CheckPCk2 = $Form.Controls.CheckBox()
$CheckPCk2.BackColor = 212,208,200
$CheckPCk2.CheckAlign = 16
$CheckPCk2.CheckState = 0
$CheckPCk2.FontSize = 8,25
$CheckPCk2.Height = 21
$CheckPCk2.Left = 105
$CheckPCk2.Text = ""
$CheckPCk2.Top = 150
$CheckPCk2.Width = 20


;KD END

$Op=SetOption('NoVarsInStrings','On')

DIM $Computer
$Computer = 'NL-KDKF7PM'
$Timer = $Form.Timer(500)
$Timer.onTimer = 'If Ping($Computer)
$CheckPCk1.Checked = "True"
Else
$CheckPCk1.Checked = "False"
EndIf
'

$Computer = 'NL-TKDBYB1L'
$Timer = $Form.Timer(500)
$Timer.onTimer = 'If Ping($Computer)
$CheckPCk2.Checked = "True"
Else
$CheckPCk2.Checked = "False"
EndIf
'

Function Ping($PC)
DIM $PC
shell '%Comspec% /C ping -n 1 ' + $PC + ' | find /C "TTL=" > nul'
$Ping = NOT @ERROR
EndFunction

$Form.Show
While $Form.Visible
$=Execute($Form.DoEvents())
Loop
Exit 1