"Operating system not found" and freezing while playing videos

I have a sony vaio VGN nw350f that keeps freezing while playing online videos and games. When it freezes the sound will keep playing but at a slower, louder, more annoying speed. Sometimes when I restart or turn on the laptop after shutting it off it will tell me "Operating system not found" or just blink _ at me. Don't know if these symptoms are related.

I tried downloading both intel and sony display drivers where at first I was able to install, now when I try to install any of the drivers it says I don't have the right drivers for the right OS.

OS: windows 7 x64

edit: I have already restored the HDD to factory default.
 
Yes you might want to find a diagnostic tool to actively scan your hard drive for errors. A tool like Seagates DiscWizard can help you understand if your hard drive is breaking or broken.

Sometimes a broken optical drive can mask your hard drive (confuse the motherboards BIOS) so that your hard drive can appear to be broken or not attached to the computer.

I'd actually check the memory on your computer first with Memtest86+ before I'd check the hard drive. Computers do weird things when they run into low level errors.
 
I'll check out the memtest

the diagnostic tool I have already tried. Twice actually and came back ok.

Does the diagnostic tool check if the partitions are corrupted?
 
I don't know a whole bunch about DiscWizard, but I'd guess that it doesn't check partitions for you.
 
OS not found ?

When you see the "O/S not found" on booting, that would mean (to me) that the hard drive is about to fail. If I was you I would make a back up of the 'C' drive onto an external hard drive, it could save you a lot of work if you need to change the 'C' drive. I do a back up of my own about once a month. It takes about 40mins.
I have used a few programs but this one is good as any and the home version is free;
http://www.runtime.org/driveimage-xml.htm

You might find your pc keeps going for some time, but the backup gives you a peace of mind, if or when it doesn't boot one day.
 
ok i ran the memtest and nothing. Would it still be a hard drive issue if I ran the diagnostic tool?

For the backing up of the HDD does it copy everything so that I don't need to install the OS again? (I don't have a CD of the OS)

and if it is the HDD, what did I do to make it break? does the HDD on laptops have a short life? (I have a 5 year old sony too and is still running)
 
Backup C drive.

The message "O/S not found" is one reason why I would be backing up the hard drive. It's a good idea anyway......
If you have a PC where the Windows O/S was installed when you bought it, then you won't have the Windows DVD.
So if you back your entire hard drive up to an external hard drive, then IF it goes wrong, you will still have to buy a new hard drive, but you would have the backup to copy over to the new drive.
(And if you don't have Windows DVD, that's £90 for W7 Home premium.)
If you did this, you may well have to 'activate' windows again, as the hard drive is different to before, but it should be ok.
Hard drives can fail very early in their life, or last for 10 years or more. It's not your fault, it's just machines with moving parts do go wrong, or wear out.
I use an Iomega 320GB, to back up my Dell to, it's that I don't fancy having to download all those MS updates again, finding all the right drivers, not to mention my music, podcasts, photo's etc. I paid £32 for my external drive, but it's not much compared to all the work I would have to do, without my back up.
As I started, it's a good idea anyway, even on a reliable PC.
 
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