Computer Malfunctions [HDD Shrink, No Video Card Detection]

I seem to have a problem. I have left my laptop on for a period of time running a heavy graphic dependant software on at the time. I come back, and my computer is very overheated, and I am at a login screen of my Vista. It says I have an invalid CD_KEY. Although I've had this computer for over a year, and been using Vista from time to time. I inputed my CD_KEY from under my laptop and it worked. I have solved that problem. However, I have 2 other problems. My HDD seems to have shrunk from 160GB to 140GB. My Graphics card also doesn't seem to detect again. I am currently running a graphic card inside my Intel Motherboard. Can I please have some enlightenment on my problem?

[EDIT]: I am using a Sony VAIO Laptop if that helps
[EDIT_2]: I am also sorry if I have posted in the wrong forum. Its just because I have various problems that fit into other branch forums.