How do I find out what ram chip is being used in my computer without opening my tower and pulling out existing chip.  I wish to increase my memory from 512 mb to 1 or 2 gigs.

Right-click on your My Computer icon and select Properties from the Drop-down menu. Click on the General Tab

Thank you for responding, but I already knew all that. It does not say what type of memory chip it is.

Down load the following free program. Its very safe, reputable and will give you and excellent summary of your system.
http://www.belarc.com/free_download.html