Gleaned the following from Adobe website:
The Nikon D3300 requires ACR version 8.4 or higher (now 9.3) which is only available in Photoshop CS6 and Photoshop CC.
ACR version 9.1.1 is the final version available for use with Photoshop CS6 .
DNG converter 8.4 (now 9.3) is provided for ustomers using versions of Photoshop older than Photoshop CS6.
ACR 8.4 and DNG 8.4 will not work on Windows XP, Windows Vista, or Mac OSX 10.6.

You could purchase the scaled down version of PS which is Photoshop Elements 13 which has a scaled down version of ACR v 9.0. But this also won't run on Vista.

So you need to either upgrade your Windows OS and download the latest DNG coverter and get PSC6/PSE 13.

Otherwise use the native Nikon software ViewNX2 or Nikon Capture. Or another third party RAW converter.