My friend took his Ram out then put it back in then when he trys to bootup the computer the computer stays on the black screen and it keeps making a beeping sound that keeps beeping. Whats wrong?

When a computer is first powered up it runs a "Power On Self Test" (POST). Many people call it a "POST test", but of course, that's redundant.

The POST runs through some basic systems, verifying that the computer is capable, at a very basic level, of running.

3 short beeps means that you have a problem with RAM.

RAM is VERY static sensitive. Your friend could have subjected the RAM to static electrical charges and not even known that he/she was doing it.

Remove the memory, put it in a static free container and take it to your local computer geek shop and have it tested. I'll include a link to a web site that lists the "Beep codes" and their meaning. http://www.computerhope.com/beep.htm