Hi Jade,
We are going to need some more information from you in order to narrow down the problem.
How far does the loading process go before the crash?
Do you get a blue screen before the crash?
Assuming that you get as far as the Vaio logo have you tried tapping F8 and booting in Safe Mode? If this is successful then the problem is probably software related.
Have you disconnected all peripherals before booting - printers, USB devices etc?
The more detail you can give the better the chance of someone being able to help.
Go n-éirí an bóthar leat
