Toshiba C660 laptop locked up whilst using firefox and did not respond to ctrl alt dlt so had to power down by pressing pwr button for 5 seconds. Now it will not re-start. Cursor flashes in top LH corner and after a few minutes boot screen flashes up briefly and only responds to F12 boot menu (will not enter F8 for safe mode etc) have then tried to boot from disc and USB which works to an extent as windows starts but then goes to blank screen.
Don't know what else to try - any suggestions please? Is this a HDD failure?