Screen freezes and then a BSOD with "Operating System not found"

Hello, this has happened twice already. My laptop (A Sony VPCCW21FX) is around a year and a half old. I would be gaming normally when my screen freezes up, and I would be presented with a BSOD saying "Operating System not found". And I would be forced to force shut down my laptop to get rid of it.The first time this happened, when I rebooted my laptop I was forced to do a "System Fix" which took around an hour. I got back onto my computer after it was done but everything was incredibly laggy until around an hour later, when it normalized but I can still notice slight lag. By lag I mean everything either takes forever to open or they freeze up with "Not responding" and I have to wait maybe a minute or two for it to return to normal.The second time this happened, I didn't have to do a system fix, I just chose "Start windows normally" and it did, but I still experienced the huge amounts of lag for another hour.I have no idea what to do, can someone please tell me what's wrong and what should I do?I've attached the analysis from the SF Diagnostic program but it couldn't found a "mini dump"This is the screenshot of CPU-Z: sjQAi.png


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Extraordinary Member
Hi mrmista and Welcome to The Forum.

We really need to see the DMP file as it contains the only record of the sequence of events leading up to the crash, what drivers were loaded, and what was responsible.

To ensure minidumps are enabled:
Go to Start, in the Search Box type: sysdm.cpl, press Enter.
Under the Advanced tab, click on the Startup and Recovery Settings... button.
Ensure that Automatically restart is unchecked.
Under the Write Debugging Information header select Small memory dump (256 kB) in the dropdown box (the 256kb varies).
Ensure that the Small Dump Directory is listed as %systemroot%\Minidump.
OK your way out.
Reboot if changes have been made.

The .dmp files are located at C:\Windows\Minidump. Until a .dmp file is generated, the Minidump folder may not exist.

Go to your C:\Windows\Minidump folder. Copy the .dmp files to a new folder on your desktop. Zip up that folder and attach to a post.

Download and run CPU-Z. Take screenshots**/snips of the Mainboard tab, Memory tab and all the slot #'s under the SPD tab.
Go to Post Reply, click on the Go Advanced button and attach the screenshots**/snips to your post for all the RAM experts to see by using the paper clip you will find on the top toolbar. Do not zip them up.
**If screenshots, please crop.

Please be sure to get all the slot numbers under the SPD tab.

Also see:

I've already posted the CPU-Z screenshots, it should be at the end of my text.

As for the mini dump, it seems like it won't create the file until I get another cr@sh so I'll be back then to post it~


Extraordinary Member
While waiting for a dmp file, a couple of drivers to sort out.

The dtsoftbus01.sys driver has been known to cause problems on some Windows 7 systems. This belongs to Daemon Tools Light. I suggest uninstalling DT Light until your blue screens are resolved. Do not replace with Daemon Tools!!

GEARAspiWDM.sys Mon May 18 13:17:04 2009 Gear Software CD-ROM Class Filter Driver v4.019.1 (Oct 2011). Also loads with iTunes

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