"Operating System Not Found"

I read other threads about this to try and figure out how to fix this issue. I couldn't find anything relating to my issue-per say.

I was copying files from my Laptop to a new Seagate external when my HD crashed. Just like the other threads, the VAIO screen will load on reboot, but it immediately goes to a black screen with "Operating System Not Found." I bought the computer from BB a year ago with W7 preinstalled. I also bought it 'ready to use' meaning the 'Geek Squad' had already set everything up and provided to recovery discs with the purchase. I have tried booting from the recovery discs, but nothing happens (bios is set to read optical drive first). I read about installing from the USB, but I don't have a W7 iso file since it was already installed.

I am working from my desktop now, but this is a major problem for me since all my design work is done from my Sony VAIO.

Any help is greatly appreciated.

Do you still have the External HDD attached as this will be giving you this error. My Sony Ericsson gives me this error due to the memory card if its connected during POST. Try to remove ALL usb devices and reboot. Resetting BIOS defaults prob would be a good one to try aswell.

Update: I went into the office because colleague of mine had this problem before and has bootable USB's that have helped in the past. I turning on the laptop and it began to 'resume windows.' I could not get this when I was at my home office. I am now running a virus scan (Trend Micro). I did notice however that some of the applications are not working properly. i.e. I can open employer, but cannot navigate within the folder, and same with outlook. I am going to let the scan run and then do a tune up utilities. If you have any other ideas or opinions, please let me know, for I am not sure this is going to cure the problem. But at least I don't have to look at the "Operating System Not Found" text anymore...for now!

Thanks

ACES

So, when you was at yours it was giving you Boot Manager Missing? Was that everytime you tried to boot? How many times did you try? And when it the office it booted up straight away so to speak with Resuming Windows? Pure random i'd say!! Lol! Whats happening with it now?

I reckon when you've moved your laptop, you have unplugged devices hence when you got to the office it booted straight away as a valid boot device was found without having extra USB devices attached (Ext HDD)!

Let us know how your getting on!

Download and install Malwarebytes, update then run from desktop a full scan.

What AV are you using? Run a full scan. If Avast, run a boot-time scan.

What are these tune-up utilities you speak of? Win7 doesn't need any tweaking whatsoever - it will almost always come back to bite you, and may have caused the problem you're dealing with.

Please post back a screenshot of your full Disk Mgmt drive map with listings, using Snipping Tool in Start menu. Attach the external HD so we can see if it derailed your boot as might have happened.

Everything is working great now. I think the problem may have occured while using my other power supply.

I ran Malwarebytes and it found some problems. After those were cleaned up, I have had no other issues.

Thanks again for all the help!