Many site issues can be caused by corrupt cookies or cache. In order to try to fix these problems, the first step is to clear both cookies and the cache. Note: This will temporarily log you out of all sites you're logged in to. To clear cache and cookies do the following:

1. Go to Firefox > History > Clear recent history or (if no Firefox button is shown) go to Tools > Clear recent history.
2. Under "Time range to clear", select "Everything".
3. Now, click the arrow next to Details to toggle the Details list active.
4. From the details list, check Cache and Cookies and uncheck everything else.
5. Now click the Clear now button.

Further information can be found in the Clear your cache, history and other personal information in Firefox article.

Did this fix your problems? Please report back very soon.

Do a malware check with several malware scanning programs on the Windows computer.
Please scan with all programs because each program detects different malware.
All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

• Malwarebytes' Anti-Malware:
  http://www.malwarebytes.org/mbam.php
• AdwCleaner:
  http://www.bleepingcomputer.com/download/adwcleaner/
  http://www.softpedia.com/get/Antivirus/Removal-Tools/AdwCleaner.shtml
• SuperAntispyware:
  http://www.superantispyware.com/
• Microsoft Safety Scanner:
  http://www.microsoft.com/security/scanner/en-us/default.aspx
• Windows Defender: Home Page:
  http://www.microsoft.com/windows/products/winfamily/defender/default.mspx
• Spybot Search & Destroy:
  http://www.safer-networking.org/en/index.html
• Kasperky Free Security Scan:
  http://www.kaspersky.com/security-scan

You can also do a check for a rootkit infection with TDSSKiller.

• Anti-rootkit utility TDSSKiller:
  http://support.kaspersky.com/5350?el=88446

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

I have cleared cache and cookies and I have run malware checks, but it does not make a difference. I should add that some (a few, not many) pages also do not load well (completely?).

If possible, can you please submit a screenshot of a website that "does not load well"?

A screenshot

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test to see if that helps.

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over the problem

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Sorry. I have not tried the above yet, because I have to go out. But I believe it is not a Firefox issue.

I installed Chrome and I can still not access certain webpages. I tried again the home page of the British newspaper The Guardian. Chrome answers: "No data received", "Unable to load the webpage because the server sent no data", "Error code: ERR_EMPTY_RESPONSE".

The home page of the Guardian cannot be empty for the last 4-5 days, and I can access other pages of the same site, such as Sport.

I assume it is either a problem of Windows or a problem with the ISP. I am in Thailand and many websites are blocked by the government, but I don't see any reason why the pages that I cannot access would be blocked.

It looks like, for whatever reason your internet browsers are not loading the CSS content. This is the code that styles the website.

I am not sure why this is.

I googled Chrome's error message and Google gives many, many entries on this issue mostly during the last six months, but without any clear solution. Some answers are also too technical for me.

I was listening to a live audio commentary of a football match and at a certain moment the connection with interrupted with the same message: "No data received" rather than "buffering" (that I would normally get).

Are there any issues with your internet connection?

Sometimes there can be issues with connection which can cause issues like this.
I experienced a similar issue a few months ago and it turned out to be my internet service provider's issue.

It may be a good idea to contact your internet service provider. It wouldn't hurt.

It is the Internet provider and it seems that the only (partial) solution is to use either VPN or the provider's proxy server, but neither option does solve the problem permanently, as far as I can understand it. For those who are interested, there is an ongoing discussion on this issue at: http://www.thaivisa.com/forum/topic/707200-true-internet-international-link-issue-how-to-resolve-instuctions/

I am glad that you were able to talk to your ISP about the issue and that you are now on the road to getting it solved.
Please report back with the details as they come.