Cant get launcher to run instead of open

[NoobToJar]

Launcher Version: Latest

Operating System: Microsoft windows xp professional

Java Version: Latest(Just updated it)

Antivirus Program: avast! antivirus

Description of Problem:

I have been haveing problems makeing the launcher run. For along time it would simply ask to open or save it, and i could not get it to run. I tried to run it from the .jar, but it would still only ask to open or save it. On my old computer, i could simply double click the .jar and it would run the launcher. Recently, when i tried to download the launcher, it would let me run it. However, i was trying to download a mod to the launcher(Bad idea) and ended up haveing to delete it and then reinstall it. I didnt save it this time though, and once i finished playing it, i tried to download/run it(From the download link), but now it is only asking to open or save again. I have heard people saying that you just need to open it with java something, but i do not know specificlly what java thing to use, because when i attempt to browse files, java is a folder with a bunch of java programs in it(Java quick starter, java SE binary, ECT.)

Error Messages:

None

Error Log:

[Jorcer]

Are you downloading the jar from IE? If so it might download with the wrong extension. To fix that all you need to do is rename the file from blahblah.zip to blahblah.jar and then run it with Java.