Greetings! I must be stupid, but I can't figure out how to do a certain thing here..

Code:

;if this old version of this file exists
If EXIST = ("C:\program files\[a certain program]\[a certain file]")
	?"Removing old program"
	RUN ("C:\WINDOWS\IsUninst.exe -y -a -f"C:\Program Files\[a certain program\a certain uninstall file location]\Uni114.isu" ")
	?"Installing new program"
	RUN (""\\network_path_to_current_file_server\newprogram.msi" /s")
EndIf


First, I would gladly accept help with the RIGHT way to type this since I currently lack the knowledge of it,
second, a question about run; does run wait until the execution is done, or does the script continue directly?

Before you say, RTFM, I did, but.. Like I said, I am stupid =)