The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

Thanks for replying!

Well, I couldn't reset it though. Everytime I click Troubleshooting Information, there's a new tab appears saying Troubleshooting Information. But the problem is there's noting on that tab/page. I mean, it's just empty. It has Troubleshooting Information title though. Hope it makes sense!

And I checked the article as well. It couldn't help me either.

Close Firefox, then when you open it hold down the Shift key. Then press the Reset Firefox button in the box that appears.

Yes, I could it do it this time. Thanks!

Now shall I check if I can upload images now? Or have I something more to do?

I just checked if I can upload now. Unfortunately the problem is still there. While uploading, a box appears saying the program is not responding and everything gets slow as well. So, therefore I've to close firefox. Or sometimes, I've to even close the computer.

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

No, it's still not working, cor-el.