I figured out the flashing command from the file, you labeled Minecraft.jar as the name of the game, but when I changed it it changed to Minecraft.jar.exe
When I changed the name to imput into cmd from Minecraft.jar to Minecraft.jar.exe, the command accepted it, and the whole thing flickered lines passed, and the game opened, but I still got the same message :'(
*edit: so if it does flash for a split second, you messed up somewhere in the path. It could be the path to the game, such as C:\Users\Yourname\Desktop\.. or the name of the game ..Minecraft.jar.exe as explained above.
I've got some tips for you guys who are renaming .exe files to look like .jar files. .exe is a Windows application (program etc) that you can run directly by double clicking on it. If you download the "Windows" version of Minecraft, this is what you should be getting.
So what, you may ask, 1.) what is a .jar file, and 2.) why should you rename your .exe file to be .jar?
Well, a .jar file is a java application which does not run on your windows machine (your pc), but it does run on a java machine. You happen to be in luck, because in order to play minecraft, you must already have the java virtual machine (a software program which can read and understand .jar files) installed on your pc, which means your pc can also run .jar files as if they are .exe files. This is a FIRST point of failure for some of you. Make totally certain that you have the JRE (java runtime environment) installed, before you complain. If you don't, it wont hurt to "google" Java Runtime. Odds are, your properly working Minecraft installer will make sure Java works on its own (if you downloaded the .exe).
The reason you were misinformed into renaming your .exe file into a .jar file is that there IS a minecraft.jar file that you can use in place of the .exe file, and some previous poster probably had the poor misfortune of not knowing how to correctly RUN a .jar file with the Java Runtime Environment, so they then renamed the .jar file to .exe hoping it would run like all of their normal Windows applications. Days of smashing their head against the wall later, this same person renamed it back, but this time managed to get it to run as a Java application through the JRE. That is likely how people would get the idea that .jar and .exe can be renamed to eachother. Nothing can ever be more ridiculous. If you are interested in what can be renamed, sometimes a .jar gets downloaded incorrectly as a .zip, and can then be renamed to .jar and be run with the JRE. But that's neither here nor there.
Well, since you can't rename your .jar to .exe, and your original and true Minecraft.exe that was never renamed still opens but doesn't work properly, the tip I have for you is that even the .exe file is really just some windows code that runs the .jar file behind your back. This is useful to know because Minecraft has memory allocation issues that cause it to crash with a black screen when the Java memory manage doesn't give Minecraft the memory it wants, when it wants it. Maybe I'm way off base here, but I've "fixed" my Minecraft many times by increasing the memory Java was willing to give Minecraft, and that can be done on the commandline (like in cmd, a shortcut or batch script), but probably only if you have the true Java version of minecraft, without the silly .exe code wrapped around it. To get that, redownload the linux version of minecraft ONTO YOUR WINDOWS MACHINE, despite that it isn't for WINDOWS. The reason this will help you is that Java programs on Windows are the same exact thing as Java programs on Linux, cause neither Windows nor Linux can run Java programs and instead, both rely on their resctive JREs to do that for them! Once your Linux version of Minecraft.jar is downloaded, you can do what andubadea or TheGuardian001 or adiktuz said to do and make a .bat file that contains the following text, and put it RIGHT NEXT TO the MINECRAFT.JAR file : java -Xmx800M -Xms2046M -jar Minecraft.jar
Another thing you can do is make a shortcut to the Minecraft.jar, rightclick it, go to Properties, click inside the Target text box in the shortcut properties and scroll all the way to the end of the shortcut and add a space followed by -Xmx2046M -Xms2046M and then click apply and OK and open the shortcut. If this doesn't work, perhaps try different numbers after the Xmx and Xms. I have a modern PC so I want it to use LOTS of memory, so I use Xmx2046. I'm not sure what you can get away with on your PC, but the number better be less than your memory capacity and more than Minecraft needs, and if you use Texture Packs Minecraft can end up using gigs of ram, sadly.
Lastly, for Leonardo7852, "do this and apear Unercognnizaded opition-jarC:/Documents
Could not create the Java virtual machine wat i do if works i will tell you my secret" seems to mean that you made some typographic errors in your Java -XmxNUMBER -XmsNUMBER -jar Minecraft.jar script. First mistake is that minecraft.jar is being kept somewhere in Documents and Settings. This path has spaces, which means your have more problems. You can solve these problems by wrapping the path to the .jar file in quotation marks, like so: -jar "C:\Documents and Settings\Leonardo\AppData\.minecraft\minecraft.jar". Another error is you forgot the space between -jar and C:\.
I'm sure I've made lots of mistakes of my own in this question answer session, but the questions were going unanswered so I figured I would give it a shot. They've actually been answered less verbosely, several times, but in the end a good answer isn't enough for the lowest common denominator, so a I added more. Good luck with one of the world's least tech supported game, with the most bugs and the best glitches. Gameplay in this game is actually governed by glitches. People use glitches as weapons, defenses, and base their strategy around them. WHen a glitch gets fixed, entire worlds need to be redesigned to no longer leverage the power of that beneficial glitch. In a game like this, a few black screens are to be expected. Also try hitting F11 and alt Tab if your PC gets swallowed in a Black Screen of Minecraft.