Was using laptop when suddendly it just switched off! Unable to restart! When I plug the power line into laptop red light comes on, it makes a noise and then goes out in a matter of seconds. Then if I press the on switch - nothing!! What could it be?!

What is the exact model? Sony has a FAQ section here:

http://esupport.sony.com/US/perl/sel...l?DIRECTOR=FAQ

One thing to try is remove the batter then try to power on with the AC adapter.

Another is also with the battery removed hold the F10 key as you power on. Or Fn F10.

It is a Vaio PGC-9S2M and does not appear on the website you mentioned. I do not have a battery for it and always use it on the AC adapter. Any other ideas? Thanks