In Opera, goto the URL opera://about and take note of the "profile" path. Then, close Opera and edit the "Local State" file there.

location {
   "country" : "us",
   "country_from_server" : "US"
}

Look for that and change the country code to see if it helps. "us" should get your Google. Not sure if any will get you Bing, but you can try different codes to find out.

@korobushka123 I just meant that it's gone from Opera's browser at least.

Yep, it's gone.

Test something really quickly. If you create a new user account on Windows, log into that and try Opera, does it work fine then?

As @sgunhouse said, you download the installer, launch it, click "options", set "install path" to "C:\Program Files\Opera", set "install for" to "all users", adjust the other checkboxes as you like and install. If you're not an admin user when you do that, you should get an elevation prompt asking for the admin password. You'll get prompted to okay the operation if you are an admin.

Once you do that, you can delete the old installation folder that's in "%LOCALAPPDATA%\programs\Opera".

That's the way you should always install Opera unless you have a reason to do otherwise. Opera defaulting to "current user" (even if you're an admin) and "%LOCALAPPDATA%\programs\Opera" is weird and was not like that in old Opera (12).

Also, if you want, set opera://flags/#autoplay-policy to "No user gesture required" while testing just to see if it makes any difference. It shouldn't, but you can try.

Also, install https://addons.opera.com/en/extensions/details/user-agent-switcher-5/ and try again masking as Chrome for Windows.

Just to see if it makes any difference, goto the URL opera://settings/system in Opera, turn off hardware acceleration, restart Opera, and try again.

In Opera, goto the URL opera://settings/startPage. Enable "Hide Speed Dial", disable "Receive promoted...", disable "Show Speed Dial suggestions", and disable "Show news...". But, make sure "Hide search box" is disabled. You want the search box on the start page to show.

Then, goto the URL opera://settings/wallpapers and disable "Enable wallpapers".

All that is to just make the startpage load faster. You can skip all those steps if you want.

Now, create a folder on you desktop named "Override Startpage".

In it, create these two files with a text editor (like Notepad):

manifest.json:

{
    "name" : "Override Startpage",
    "version" : "0.1",
    "description" : "Override Startpage",
    "permissions": [
        "tabs"
    ],
    "background": {
        "scripts": ["background.js"]
    },
    "manifest_version": 2
}

background.js:

var page = "https://www.google.com/";
var start = "chrome://startpage/";

chrome.tabs.onCreated.addListener(function(tab) {
    if (tab.status === "complete" && tab.url === start) {
        chrome.tabs.update(tab.id, {
            url: page
        });
    }
});

chrome.tabs.onUpdated.addListener(function(tabId, changeInfo, tab) {
    if (changeInfo.status === "complete" && tab.url === start) {
        chrome.tabs.update(tabId, {
            url: page
        });
    }
});

Then, in Opera, goto the URL ```opera://extensions`. Then, switch on Developer Mode at the top right. Then, click the "Load unpacked" button and point it to the "Override Startpage" folder that's on your desktop.

Any time you want to change the page that's loaded, edit the "page" URL in background.js and click the reload button next to the extension on the opera://extensions page.

You can then goto opera://settings/onStartup and adjust settings there too if needed.

@Daigo Thanks for the clarification.