I have had an Acer Aspire One D255E for over 6 months and all was fine until today. On turning it on I get 'no bootable device - insert boot disk & press any key'. The only other thing I can do is press F2 to mess with settings (which I haven't done). The machine makes a new noise as if it is looking to boot-up but it can't find the groove. Any ideas as to what to do?