Still looking for an answer. my daughters computer did this and we need it for school too
Hi Heather,
In the end our problem turned out to be a depleted battery. Bizarrely we had to wait for the battery to completely discharge before it would restart so we left it unplugged overnight to let the remaining power drain away and then plugged it back in the next day and it worked as normal. After it switched on we left it to fully recharge the battery before using and all was good. It has happened a few times again since then and we think the reason is because the power supply connector occasionally works loose or isn't plugged in tightly enough and consequently we thought it was running off of mains power where as it was actually running off of the battery which, when it gets low enough, triggers the "Windows Locking" alert and disables/shuts down the PC.
With kind regards.