If you are reading this post than you already know the answer: neither Sony nor NVIDIA have given you the blessing to install Windows 7 64 bit. So officially it is not approved or supported by booth companies. Well then, the question is can you do it? The answer is yes, absolutely! Will there be any tradeoffs or shortcomings? Yes, indeed. So, let’s begin. 1. First your priority will be to enable virtualization (VT) and AHCI support in BIOS. Check your BIOS version by pressing F2 key during reboot. Upgrade to version R0096N0 (if you have a different version) from: Sony eSupport - VGN-SZ340P - Support For BIOS R0096N0 (see guide here): How to Enable Intel VT and AHCI on a Napa/Santa Rosa platform Phoenix BIOS Vaio laptop) AHCI: (0165)  ---> (0165)  VT-x: (0399)  ---> (0399)  Note: *I have actually upgraded my BIOS from R0096N0 to R0112N0 For BIOS R0112N0 AHCI: (015C)  ---> (015C)  VT-x: (0354)  ---> (0354)  2. Now run install from Windows 7 PRO 64bit DVD or USB bootable flash drive. Use the graphics hardware switch in position Stamina. After the installation process has finished and your laptop has rebooted, you will find three unknown devices in Device manager, including: -Other devices: Mass storage controller -Unknown device -Unknown device Now is the time to install Universal Extractor 1.6.1 from: Download Universal Extractor 1.6.1 - FileHippo.com To make the installation of all Sony drivers and utilities trouble free, please unpack them after download to subdirectory first and then run installation from there as an administrator. In Device Manager right click with your mouse on mass storage controller and choose properties. Go to details tab and in Property scroll down list click, Hardware Ids. Copy last line: PCI\VEN_104C&DEV_803B&CC_0180 and paste into Google search to find sources for driver download. Here is the link: Windows XP and Vista (32/64-bit) TI Media Card Reader Driver 3. Driver for “Unknown device” with hardware Id: *SNY5001 can be located the same way as described above. Also you can install it by simply running Windows update, which will download and install driver Sony Firmware Extension Parser ver.22.214.171.124 Or use this link: Windows 7 Individual Drivers and Utilities : Download : Sony Asia Pacific 4. Driver for “Unknown device” with hardware Id: *SNY6001 can be located using Google search engine or download Sony Programmable I/O control device ver.126.96.36.199 from link: Windows 7 Individual Drivers and Utilities : Download : Sony Asia Pacific *Remember to restart your laptop after each driver installation. 5. Install Microsoft Visual C++ 2010 Redistributable Package (x64) Download Microsoft Visual C++ 2010 Redistributable Package (x64) from Official Microsoft Download Center 6. Install Toshiba Bluetooth Stack 7.0 from: Toshiba Bluetooth Stack - Download Now we will install Sony controls and utilities from: Original Drivers and Utilities for VPCE Series (Windows 7 64Bit) : Download : Sony Middle East & Africa. Restart after each individual control installation. 7. Sony Shared Library ver.188.8.131.5250 Vaio Event Service ver.5.3.0.05310 Setting Utility Series ver.5.3.0.07231 Vaio Control center ver.4.3.0.05310 Vaio Power Management ver.5.2 (Optional: Original Drivers and Utilities for VPCE Series (Windows 7 64Bit) : Download : Sony Middle East & Africa) Wireless Switch Setting Utility ver.3.6.01.18210 (Wireless Switch Setting Utility Upgrade Program Version 3.6.01.18210 : Download : Sony Asia Pacific) 8. The most important driver is for NVIDIA GeForce Go 7400. It is very clear (from numerous internet searches I have run) that most folks give up on Windows 64 bit install at this point. Needles to say that no driver released by Sony or NVIDIA support this graphic card. So the only solution is to use modified INF file from laptopvideo2go.com. It is only way to install the driver in 64 bit system. Download NVIDIA driver ver.197.25 for Windows 7/Vista 64 bit first, and then save to your desktop. Unpack 19725_win7x64.exe to subdirectory using universal extractor. v197.25 Windows 7/Vista 64bit | NVIDIA Desktop - 19x Series GeForce Driver Releases - LaptopVideo2Go Forums Click on download link for inf modified. It will open a text file in your browser window. Simply highlight all the text or press Ctrl+A instead, right click and choose copy. Open notepad and paste highlighted text. Save file as: nv_disp.inf on desktop. Now, open the folder where you have extracted 19725_win7x64.exe file and rename the file nv_disp.inf inside that folder to nv_disp.inf.original. Return back to desktop and copy nv_disp.inf file, paste it into extracted folder. Now slide the graphic hardware switch to speed position and restart laptop. At the end, run setup.exe as administrator from extracted folder. Reboot and enjoy Windows 7 64 bit. I have run windows experience index and got a score of 3.6. It is up from my previous score of 3.5 I had on Windows 7 32 bit before that. Do not expect that brightness controls on keyboard (FN+F5, FN+F6) will work. S1 and S2 will not work also. For me it is not a big deal. Here are some other options. Click on the Control panel and save shortcut of Windows Mobility center to your desktop; it has a slider to adjust brightness as needed. It also controls screen input to other source or you can press Windows logo key +P to accomplish similar results. Congratulations and enjoy!