My full spec :
OS - Windows 8
Nvidia GTX 960
8GB of RAM
It's just happen yesterday when i forgot to turn it off then when there is a short blackout then when i woke up i press start it won't boot its just stuck there i keep pressing f12 and f8 but won't do anything its just repeating
If you are able, to it may be that the RAM is unseated properly and may need to be reinserted, IF you are able to do so, power off remove the battery, remove the ram and ensure it is reseated properly, or try put it in the other memory slot.
i had an issue like this a few years back , turned out memory stick had somehow dislodged.
Please do this if you like at your own risk however, it is only a suggestion.