Hi all, I am using a Sony Vaio laptop for 2 years, but it has been frozen at the desktop lately. Whenever I start the machine, it runs till desktop and frozen there, nothing work, even the Ctrl+Alt+Del. I have tried with safe mode but nothing seem to be working. I would be really appreciated if someone and give me a clue about how to fix it as I need some important data from it. Thanks,

Boot to the Safe Mode screen and try Last Good configuration.
Try a repair install:
http://www.michaelstevenstech.com/XPrepairinstall.htm
If all else fails, it's relatively simple to remove the HD and copy the files to another medium.