If you are in Windows, any version, it's probably either your Browser has been set to a lower resolution or your screen itself. Here's how to "fix" these problems.
Open your browser and hold down the "ctrl" key. Then press the "-" sign to make things smaller. Do this repeatedly until the screen is at the resolution you wish.
If this doesn't work and you find the same thing in other browsers and programs it's probably a problem with your video settings or your video sub-component. Here's a set of steps to "fix" that (if it can be fixed)
Close all programs but Windows. Right mouse button click on the desktop. A small menu will appear. One line from the bottom it will say "Display Settings" Click on that. It opens the settings for the display (wow, what a surprise! LOL!). Sort of near the middle top it says "Display" Straight down from that a few inches and other options, it says Scale and Resolution. Under that two lines is "Display Resolution" If that is set to your recommended settings, leave it alone. If it's set to anything else select the down arrow head at the right of the box, open the menu and select the recommended display settings. That should fix it...if it's just a setting error. Unfortunately, often the reason it went to another display setting (usually a lower one) is often a hardware or software error. To fix that, here's yet another set of instructions.
Every piece of hardware in your system has some coding to make it able to talk to all the other parts, or at least the parts two which it needs to speak. That software can go south. When it does the system will grab the "standard" Windows software and use it. That standard software is really the minimum needed and has none of the whistles and bells of the mfr supplied software, including some higher levels of resolution. So we need to attempt to repair that software. Here's how to do that (or at least one possible way).
While at the Windows desktop right mouse button click and pull up the menu you used to try to reset the resolution. Below the display resolution button you will see "Personalize" Click on that. Now you have opened a screen in the Windows setup program. At the top left of that screen is the word "Home" Hit that. At the top center you'll see a search box. Type "Device Manager" and hit Enter. The device manager will be the only thing it finds. Click on it. This opens a long list of the hardware in your system. About 3 or 4 lines from the top it will say "Display Adapters" Click on that. Now for the fun part.
What's listed in this area will vary from system to system. In general it tells you the name of your display component. Write it down as you may need it later. If your drivers (the software the mfr supplies) is screwy, it may say "Windows Display" or some other generic name. Doesn't matter because anything in this area is going "bye-bye" Right mouse button click on each item (there's usually only one but might be two or three) and click on "uninstall". Do all of them. It will ask you if you wish to remove the software, but not yet. The easier steps first as removing the software may not be necessary.
Once you are done it may ask you to restart your system. If it does and you've closed everything but this screen, say okay. If not, close everything up and wait a second as it may reinstall the drivers at this point. If it does, reboot anyway.
Now once you get back in, if the resolution is still screwed up try the first step again and reset the resolution to "recommended". Probably won't work, but once in a while it does. Lucky you! On the other hand, if you are "unlucky you" and it still kicks back to the lower resolution, you'll need to go through this last procedure and and this time click on "remove drivers" when asked. Then reboot and let it try to reinstall them from scratch.
Now if none of this works there are two more things. Since the drivers are obviously corrupt or the hardware is broken, you need to fix the corrupted software. To do that go to the display mfrs website, download the software for the display adapter you wrote down (you did write it down, right?), and install it. Reboot and see what happens.
Finally, if you've done all this and the stupid %$*%^# thing is still in low resolution and refuses to play nice, it's a hardware thing. Sadly that's a trip to the shop and/or a whole new system, depending on if your video subsystem is built onto the motherboard ("integrated," as they say, which is probably true if you bought off the shelf hardware) or independent. Independent means you can replace just it. Integrated means you have to replace the entire main board (also called motherboard).
Well, I hope you only had to do one of the opening things and haven't had to read this far. But if you did read this far and things are fixed, Yay!. If not, here's what I feel:
AJ