Hi,
Did you install KB2919355 after you installed 8.1? That's the Windows 8.1 update which introduced the power and search buttons at that location.
You can check by doing the following.
- Right click the Start button and go to Programs and Features at the top.
- Click the link to "View installed updates" in the menu which appears and then copy/paste KB2919355 into the Search field top right. It shoud appear below immediately.
If it's not there, download it manually from here: https://www.microsoft.com/en-us/download/details.aspx?id=42335
When you click the red Download button in the above link, you'll see a list of seven files. Click the box at the top called "File Name" which will select them all and then click the
Next button. Then follow the prompts from there.
If KB2919355 isn't installed, you may possibly get one or more installation errors when you try to install it. There's a hotfix available for most of these which you'll find about two thirds of the way down the page in the following link under the heading:
Known issues with this update: https://support.microsoft.com/en-us/kb/2919355