Cannot open particular website in Chrome, Firefox, Edge, IE OR windows not connecting to particular websites

1] Delete your browser cache
First I suggest you clear your cache and try again. Best to use freeware CCleaner to do the cleaning job. Reboot and try again. Else you may start Internet Explorer from the desktop. From the Tools menu, select Internet Options. Under Browsing history – viz. Temporary Internet Files and Cookies – click Delete. Select all the applicable check boxes, and then click Delete. Now try and see if this helps.
In Edge, you will find the option to Clear Browsing History under Settings and more. Similrly you can clear the browser cache in Firefox and Chrome as well.
2] Run an antivirus scan
Scan your computer with your antivirus software, as it is quite possible that it could be a malware wanting to prevent opening of a particular site/s. Please also ensure that none of your security software or firewall is blocking the site.
3] Reset Hosts file
Next, have a look at your Hosts file. The Hosts file contains the mappings of IP addresses to hostnames. It is situated at C:\WINDOWS\SYSTEM32\DRIVERS\ETC. Open it with Notepad or better still get freeware small utility Hostsman to have a look at it. Check if the site you want to open is mentioned there. If it is present there and if it has the numerals 127.0.0.1 your web page probably won’t open as it is the most commonly utilized address for localhost. If you feel that your Hosts file has been hijacked, you can download and reset Hosts file.
4] Add to Trusted Sites zone
Add the particular website to the Trusted Sites list, and see if it helps. To do so Open Internet Options > Security Tab > Trusted Sites > Click Sites > Uncheck ‘Require server verification’ checkbox. Now, in the ‘Add this website to the zone’ box, type the URL of the site as, say: https://www.thewindowsclub.com and click Add. Then click OK.
5] Check Restricted Sites
You may also want to check if the particular site is blocked. Check Internet Options > Security Tab > Restricted Sites > Sites. Here you can see the Restricted Sites. I suggest you use ZonedOut utility to Add, Delete, Import, Export, sites to this zone and manage Internet Explorer Security Zones.
6] Reset Zones to default
Open Internet Options. In Security click ‘Reset all zones to default level‘. Click OK.
7] Use Proxy site

From the affected system, see if you can visit the particular site from a proxy site, like kproxy.com, etc.
8] Flush DNS cache
Check if you can visit the particular site with its numerical IP addresses. Incidentally, microsoft.com is the most commonly blocked site, by malware. So for example if it is microsoft.com, see if you can visit it with any of these:

• http://207.46.19.190
• http://207.46.193.254
• http://207.46.19.254
• http://207.46.192.254

If you can access it via the IP’s, I suggest you flush your DNS cache.
9] Disable Add-ons
Sometimes, some incompatible IE add-ons could be the reason for the conflict.  Disable these add-ons in the first place. To disable add-ons manually and to run IE in no add-ons mode, open Internet Options and under Programs tab look for ‘Manage Add-ons’ button. Click the button.

In the Manage add-ons window, click ‘All add-ons’ option.

Click each add-on individually, hit the Disable button. When you are finished, tap or click OK. You can manage the following types of add-ons

1. Browser helper objects
2. ActiveX controls
3. Toolbar extensions
4. Explorer bars,
5. Browser extensions
6. Search providers
7. Accelerators, and tracking protection settings.

This post will show you how to disable add-ons in Firefox and this one on Chrome.
10] Clear the SLL state
If you are connecting to a secure website, your browser may be usinh an encrypted channel equipped with Secure Sockets Layer (SSL) technology to encrypt transactions. If the information in the SSL gets corrupted at any point of time, the website may fail to load correctly.
As a corrective measure, clear the SLL state as follows:

• Open Internet Options in the search box, and then choose Settings.
• In the search results, click Internet Options. Hit the Content tab, and then click Clear SSL state.

11] Check system date and time
At times, Incorrect date and time settings on your PC can cause problems accessing webmail servers. So, make sure that the date and time settings are correct on your PC. Do the following:

• Type Date and Time in the search box of the Charms bar, and then click Settings.
• Choose Date and Time from the search results, and click Change date and time.
• In the Date and Time Setting window, set the current date and time.

12] Disable Enhanced Protected Mode
Enhanced Protected Mode is a new feature in Internet Explorer. To disable it, if it prevents you from opening web pages in the Internet Explorer do the following, If some web pages are not displayed In Internet Explorer, even if the computer is connected to the Internet, try the following:

• Open ‘Internet Options’ and switch to the ‘Advanced’ tab.
• Next, locate the checkbox ‘Enable Enhanced Protected Mode’.

• Uncheck the box. Hit the Apply button and then click OK. Restart Internet Explorer and check to see if the issue is resolved. Please note disabling the Protected Mode may enhance the performance in Internet Explorer but could leave your computer at risk for possible attacks.

13] Check Proxy and DNS Settings
Proxies provide you with more privacy if you are simply connecting directly to the internet. By default, your browser automatically detects proxy settings. However, if this setting has been tampered with you may experience the problem in connecting to the desired network. To verify if all is well with the proxy settings, follow these steps.
Open ‘Internet Options’ > Connections tab, and then the LAN settings.

Click ‘Automatically detect settings and check if there is check mark against it in the box.

14] Reset your browser

If the problem persists, it is likely that some unwanted changes were made to your installation and therefore stopping you from viewing some websites.

• Reset Edge
• Reset Chrome
• Reset Firefox
• Reset Internet Explorer.

15] Start Windows in Clean Boot State
To start Windows in Clean Boot State, type MSConfig in the Search box of the charms bar and then click open the System Configuration screen.
Tap or click the Services tab and select the Hide all Microsoft services check box, and then click Disable all.

Now, click the Startup tab. Open the Task Manager to manage Start Up items. Then, click Disable all in the bottom right corner, and then click OK.
After following the above procedure, you will be prompted to restart the computer. Do it, and test your browser for an online connection.
If you find that it is now working, it means some program is creating problems. To identify the conflicting service or program, select half of the listed items, and then click OK. Restart the computer, and then test your browser again.
Repeat steps until you identify the service that is conflicting with the browser. If you find a service conflicting, remove it or configure settings so that it doesn’t start when the computer is turned on.