If you are unsure of which version of Windows you have, start with the Windows 10 instructions, and if you do not see the gear icon in Step 1, then you have Windows 7.
If you need to force a restart on your Remote Desktop because you rejected the restart prompt, you can do so by hitting ctrl+alt+end and then using the power button in the bottom-right to restart.
To update Windows 7 (typically has the rounded Windows start button)-
1) Click on the Windows Start button. In the Search Bar, search for Windows Update. Then select the Windows Update from the top of the search list.
2) Click on the Check for Updates button. Select any updates that are found and install, Restart if prompted.
3) Repeat steps 1 & 2 until no further updates are available (it may take a few rounds depending on how many updates you have missed).
To update Windows 10 (typically has the square Windows Start button) -
1) Click on the Windows Start button, and then go to Settings (Gear icon) > Update & Security > Windows Update .
2) Install all available updates, and restart if prompted.
3) Repeat steps 1 & 2 until no further updates are available (it may take a few rounds depending on how many updates you have missed).