Vista Home Premium locked up on 5/12/10 while on a website and could not get to 'control-alt-delete.' Mouse locked, too. On/off switch would not work (stayed lit) so I unplugged the power cord. When I tried to re-start the computer I could hear a fan running but it would not boot up, nothing on the monitor and no lights on the keyboard. O/S was preloaded so I do not have a boot disk.I tried pressing F1, F2 and F11 and also with monitor off but nothing worked. Computer has not been been moved or abused so all internal connections should be fine. Have updated Windows Vista Home Premium regularly and also updated Avira anti virus and anti malware programs regularly. Using Firefox and Vista Home Premium O/S. Computer is 2 years old and was purchased new from Best Buy.