I have an older sony vaio laptop, model PCG-K315B, I am currently not able to load the operating system as once the PC is switched on the Error Message: 'Error loading operating system' is displayed. I have attempted the F10 system recovery, following the wizard and selecting 'complete recovering' (also tried c:\ drive only), this starts to run but around 25% this fails and then the following error message: 'Failed to read the image file, recover the computer again. When I repeat this it fails at the same point.

It this something that I should take for repair, with it being an older PC is it worth getting repaired?

Are you getting a dos prompt? If so, type ckhdsk and let it fix any errors.

no dos prompt. When the PC is switched on I press F10 when the Sony Vaio logo loads. Is there a way i can get to dos prompt?

How about safe mode? To get to safe mode, press F8 just before windows begins to load. You will see a menu, select safemode and see if it will boot. If it does, click on your "My Computer" and right click on your c drive then properties, tools, error checking and let it run if it will.

Also previoulsy tried F8 but this doen't work. It will still display the 'error loading operating system message'.

I was having issue myself. Recovery stops at 75%. ever since I upgrade my Ram I started having issues. I thought this time Id put the original ram and restart recovery. So far, im having success. Make sure you have all factory device in your laptop.