Generally programs will grab the memory needed to run from what is available. When you know that you will be running large programs like some new games out with intense graphics you would then things that startup with Windows to free up memory. You can disable or enable even modify the system page file to change the size of the hard drive space used for virtual memory. For the specific means of allocating and freeing memory there are some freeware utilities you can look over at: http://www.freewareaid.com/utilsmemory.htm Assigning a specified amount of memory to one program is usually performed by writing the programming lines for it.
hi thanks for the help, and btw the computer im using isnt the one in my sig...that one is currnetly being reparied... its for a dell dimension 8400
p4 3.0ghz
512mb ram
72 000 rpm hdd