Installing and upgrading help

Thanks I've already installed 4 windows complete installed moodle in a single localhost and a server using single apache, php and mysql... with 4 different URL and can use in live Site but this kind of proccedure will eat a lot of memory. The good news of this is that it can mixed up with different Version if you like.... I tried to installed 1.9.5+ and 2.0 in a single installation and it works well...Truly memory and Performance will be affected. So for everyone wants to dare to make this kind of proccedure make sure that your server have a huge memory.... That's all..