How to adjust slide and shapes by pixel

You have never had to make a pixel map or anything that is required to be pixel accurate. Most consumers don't think about pixel accuracy, but that's the only way we work in the entertainment industry. We deal with resolutions every day, in inability to have a proper pixel conversion in software as basic as PowerPoint is beyond ridiculous. 

Either way, Microsoft Office 2013 has failed to provide me with a solution for something I need and use regularly. Back to Mac I go.

It's unfortunate, but the answer to this problem is simply the fact that Microsoft eliminated a feature that is much needed for anyone who works with pixel accurate media and I'd imagine anyone who works with web-based stuff as well.

Thank you all for your attempts at helping me solve this issue.

Unlike Word, in which you can set the units of measurement, PowerPoint pulls the units of measurement from your computer system. So to change from inches to something else in PowerPoint, you have to make the change in the measurement system settings in Windows Control Panel. Unfortunately your only choices here are US and Metric, so pixels isn't an option.

You can use points if you prefer.  Instead of entering just a number in any of the size dialog boxes, enter the number followed by pt.  72pt for example rather than 1 inch.

This is your answer right here. If you want to create a slide that is exactly 1920x1080 pixels, just enter '1920 pt'. As soon as you hit tab or enter it will just convert that to mm or inches. Keep in mind that source images should be at 72ppi to translate 1:1. 

As another industry professional it still does baffle me why powerpoint doesn't have pixels as units of measurement. Projectors and screens deal in pixels. Printers deal in cm or inches. Powerpoint is literally designed for presenting, not printing...

I've only tried this in PowerPoint 2013, but in the size adjustment fields just overwrite "cm", "inches", or whatever it says in your PowerPoint with "pixels" and it will resize to exact pixel size.

It will revert the unit to whatever your PC settings say, but the size will be in what you set it to be in pixels.

When exporting it doesn't adhere to this (something I still have to work out myself), but copy/paste to another program like Paint and it will be the exact size you set it to.

...and all of you guys challenging why this is needed in the first plase, please "put a sock in it". When someone asks a question, I'm sure they have a good reason, so there's no reason to be obnoxious about it.

Like Steve I can't see the advantage of working in pixels. But I think in most recent versions the conversion would be 96 not 100. You may not need to work this out in your head. In the Height / Width boxes in the FORMAT tab try typing eg 288px. It might do the calculation for you.