Is this with all websites/pages, some, a few?

What were you doing at the time? surfing, watching a clip, reading something . . . .

When does it happen the first time?

Start Firefox in Safe Mode {web link}

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

Is this with all websites/pages, some, a few? What were you doing at the time? surfing, watching a clip, reading something . . . . When does it happen the first time? Start Firefox in Safe Mode {web link} A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

it is for different websites, sometimes surfing the internet, Facebook, gmail , sometimes youtube ... Well the first time this happened after i bought a new laptop Dell Vostro 3590, I thought it is because of an old driver, but i updated all of them, with the same problem. I never use Google Chrome so I don't know if it is the same problem or it is something related to Firefox I tried Safe mode, I tried without add-ons, and i even Refresh it with the same problem still!

See if the problem happens with other web browsers.

https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix

https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram

https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

https://support.mozilla.org/en-US/kb/firefox-takes-long-time-start-up

https://support.mozilla.org/en-US/kb/quick-fixes-if-your-firefox-slows-down

MemTest LAST UPDATED : 27/09/2013 Could you please run a tool from http://memtest.org/ in order to check the integrity of your RAM?

You will need a thumb or disk drive to install it on.

Do you let Windows handle the page file or did you set a fixed size ? If you use a fixed size for the page file then try the former and let Windows handle the page file.