Thanks for sharing that info... looked up your laptop here:
http://www.msi.com/product/nb/CR630.html#hero-specificationWas trying to find a picture of the bottom of this model to see if there was an access panel to remove to get to the hard drive to upgrade easily, but from top and side view construction of this laptop it looks like it may be one of the more difficult ones to upgrade the hard drive in.
Looks like you have probably the 320GB HDD.... so the question now is, do you really need all that data on that 320GB SATA HDD to be on it all the time or can you unload some data that you dont need all the time to an external hard drive.
I have a laptop with a similar CPU that is a Toshiba that also came with a 320GB HDD and the biggest waste of space on mine has been loading up many large install games such as Aion, World of Warcraft, SWTOR, Tera Rising, Diablo III, Starcraft II, and many others. To free up space on my laptap when I got down to just 60GB free of the 320GB HDD, I moved almost 40 GB of videos and pictures to an external HDD that my camera kept downloading to it every time I joined the camera and laptop together with USB cable. I also removed games that I no longer played or ones that I rarely ever play. Games that I rarely play, I copied to my external HDD so that if I wanted to play them later at some point i wasnt having to redownload 25GB etc.