If you want to get fancy, you could set it up to run automatically on boot. You need to create a folder on the SD card called 2577. You would then put your mortscript.exe, autorun.exe and autorun.mscr in that same folder. WM will automatically run the autorun.exe everytime you boot and anytime you insert the sd card. Here is my autorun.mscr and you will see how I got around it popping up a run dialog all the time. Note that I use mine to run tiermann autoinstaller, but you can modify to your needs.
My autorun.mscr
Code:
If ( RegValueExists("HKLM", "Comm", "NoRun") )
Exit
EndIf
If (Question("Do you want to run Tiermann Autoinstall?","Install programs","OkCancel")=CANCEL)
Message ("You will not be asked again.")
RegWriteString("HKLM", "Comm", "NoRun", "NoRun")
Exit
EndIf
RegWriteDWord("HKLM", "Comm", "AutoRunFlag", "0")
RegWriteString("HKLM", "Comm", "AutoRunCFG", "\Storage Card\2577\TAutoInstall\Config.txt")
RegWriteString("HKLM", "Comm", "AutoRun", "\Storage Card\2577\autorun.exe")
Run("\Storage Card\2577\TAutoinstall\tautoinstall.exe")
This script runs on every boot, but first looks for a registry key. If it doesn't exist, it will ask you if you want to run the installer. If you select no, it writes the key which prevents the popup on future boots.