I have Windows XP, it says I have 512 MB of RAM. I have Adobe Photochop Elements 7 that I want to use on my computer. On the package ii says I need 1 GB of RAM and 1.5 GB of available hard disk space. Two questions, is MB bigger than GB (do I have enough RAM) and if not how do I get more RAM? Second question- how do I find out how much available hard disk space I have? I'm not very computer savvy if you can't already tell. Any help you could give me would be appreciated!

Thanks