Crazyace,
I am sorry I didn't fully explore your code last time, and just went directly to answering your questions. I have modified your code a bit so that it will perform more to your needs. I noticed from your original post you had a large sleep function at the bottom to keep your GUI open. When a button is pressed during sleep mode, it will not perform your needs. You need to create a loop after your gui creation to watch for user input and activity. Hope this helps a bit.
#include <GUIConstants.au3>
GUICreate("Drivers/Manuals/Warranty", 280, 110)
$Driver = GUICtrlCreateCheckbox("Drivers", 10, 10)
GUICtrlSetState(-1, $GUI_CHECKED)
$Manual = GUICtrlCreateCheckbox("Manual", 80, 10)
$Warranty = GUICtrlCreateCheckbox("Warranty", 150, 10)
GUICtrlCreateLabel("Service Tag #:", 10, 45)
$Input = GUICtrlCreateInput("", 90, 40)
$Submit = GUICtrlCreateButton("Submit", 40, 70, 50)
$Exit = GUICtrlCreateButton("Cancel", 150, 70, 50)
GUISetState(@SW_SHOW)
While 1
$msg = GUIGetMsg()
Select
Case $msg = $GUI_EVENT_CLOSE
ExitLoop
Case $msg = $Submit
$serv_tag = GUICtrlRead($Input)
If GUICtrlGetState($Driver) = $GUI_CHECKED Then _Fire($serv_tag)
Case $msg = $Exit
ExitLoop
EndSelect
WEnd
Exit 0
Func _Fire($sServiceTag)
;IE functin that will handle $sServiceTag that is the passed input read from control $Input
EndFunc
Realm
Edit: If you are using Scite, this only works for the AutoIt version that was included with the standard Install, to create your scripts, you may also type 'setupgui' then press space and it will create a basic template shell of a gui window code for you, including the while loop.