First off, is there any reason you haven’t yet updated? DEX 2 was replaced by DEX 3 almost 3 years ago now – and it’s a completely free update that uses dynamic skins that automatically resize to fit any display.
Regardless, if you wish to use the older DEX 2 version, this will fix your problem:
With DEX 2 CLOSED go to Documents -> PCDJ-DEX -> Settings. In that folder DELETE the file labeled ‘preferences’ and then re-launch DEX 2. It should default back to the original skin and the software will automatically select the best skin size for your screen resolution.
If you wish to download your free update of DEX 3, simply download/install it from this page (with DEX 2 closed). It will NOT overwrite DEX 2, but it will pick up the DEX 2 activation code. Therefore DEX 3 will open up in full-version mode ready to use: http://www.pcdj.com/support/dex-3-support/
DEX 3 uses a much more modern method for the skin, as well as modern methods for everything else. It’s a far better product than DEX 2!
You can check out all the DEX 3 video tutorials here as well: https://www.youtube.com/playlist?list=PLYCb1_l2bbb735qXxerqr2dVDXu2qVYet