Windows 10 Sony Vaio Brightness Issue

Hi Sandz,
trouble is Sony isn't releasing new drivers any time soon. I popped on the support page for your machine (the usual place you find laptop drivers) and found this message re Windows 10:

Windows 10 information - July 17 Update

As announced by Microsoft on June 1, Windows 10 - their latest operating system - is scheduled to launch on July 29.

WARNING: There is a risk of software/driver corruption. We therefore strongly recommend that you do not upgrade to Windows 10 when it becomes available on July 29.

Sony is now testing Windows 10 and will be providing compatibility information during the summer of 2015. The release schedule will vary according to the different products.

With regards to Sony VAIO personal computers, we are preparing a Windows 10 upgrade procedure – together with the necessary drivers and software* – for compatible models released after October 2012 (which were delivered with the Windows 8 or Windows 8.1 operating system preinstalled). Please note that Sony is currently not planning on providing an upgrade procedure, nor drivers and utilities, for older models which were released with Windows 7 or previous versions of Windows preinstalled.

Please wait until the upgrade information is released. Visit our support website regularly for the latest information and updates about this topic.

*Note that some of the functions, utilities or other software on your computer might be missing or not working properly after the Windows 10 upgrade.

Click to expand...

http://www.sony.co.uk/support/en/content/cnt-hn/prd-comp/windows_10_information/VPCS13L8E

So I guess for a while at least support is going to be patchy. Some upgrades run better than others depending on the state of the os, what applications were installed and whether anti-virus was enabled or not (when upgrading it should be turned off). All I'm saying or trying to say is that these variables will effect the outcome of the upgrade which is probably why your seeing a difference between the two machines.
Microsoft did release two large patches which I know fixed a few things for people so make sure yours is fully updated by running the Windows update app. You can find it via the start menu and settings. Click on the update icon and then check for updates.

Edit:
The thought just struck me, it might be worth posting in the Sony forums to see if anyone else has had the same issue and found a fix?
Vaio - Sony Insider Forums


I also did a little search on your issue. Some found updating the graphics driver helped. You could always try the Windows 7/8 graphics driver off the support page?
Link Removed
Try installing the driver under compatibility mode.