Are you able to boot in to safe mode, OR are you able to access the system BIOS? The procedure to enter the BIOS varies, but is usually a function key, such as F12 or F2. IF you can get in to the BIOS there may be a hardware diagnostic you can run.
EDIT: I googled it, and found out most Vaio laptops require you to press F2 at startup to enter the BIOS.