What the heck?
Dehaze is only available starting with LR 2015.1, and is not part of the LR 5 or LR 6 series, only LR CC, until LR 7 assuming there will be a LR 7.
The solution would be to install LR CC on your PC unless you can't because it's a 32-bit OS, where LR CC (and LR 6) requires 64-bit OS. And then your only solution is to install a 64-bit Windows on your PC unless you can't because it's not a 64-bit CPU, then the only solution is to replace your motherboard or your entire computer with one that has a 64-bit CPU and install a 64-bit OS, probably Windows 10.
If you have Dehaze on your Surface Pro, they you may already have a Creative Cloud license which does allow for installation on two machines.
If you're not seeing the Lightroom CC 2015 update on your PC, it's possible your OS doesn't support it - as Simon suggests above.
This is very frustrating.
I do not own a software version of Lightroom.
I have a 64bit PC running Windows 10.
I downloaded CC Lightroom and Photoshop first onto the PC and then onto a Surface Pro 3.
I have been using CC for almost two years.
I get the update notifications on both devices and keep current.
I don't even care how I got the wrong version of LR, I just want to know how to fix it.
Is something called "Adobe Lightroom" installed in Control Panel - Programs & Features? If so then you probably just need to find the correct shortcut for LR CC 2015 and run it, instead of the LR 5.7.1 shortcut. On my Windows 10 PC the correct shortcut is under Start / All Apps / Adobe Lightroom
If Adobe Lightroom is not installed on your computer then install the CC App from here if necessary, then the Lightroom app from the same place: