This browser isn't working out for me with Windows 8.1, I've decided to go with Chrome & Firefox.

Yea, it being lagging since many updates ago (a reason Google Chrome is now my fav) i just come here today to c if there is a better update, i updated to Opera21 and discovered that the same problem still persist.
Conclusion: Opera is not developed for w8 and higher.

I see, so it does have issues on Windows 8.x in general then.

Are there any Opera extensions/add-ons installed ?

Yes actually! two of em' :

Chrome's AdBlock Plus extension
& the Bookmark extension by the Opera Team.

But I later removed the Bookmark extension after setting them up on the bookmark bar, tried with AdBlock Plus disabled (but not removed) ...however the problem persists.

Okay, I'll try what you suggested and see what happens but for the record, it doesn't only happen when multiple tabs are opened. It also happens when I launch Opera 21 with just the speed dial page opened, which I have no sites on because I hate the speed dial on a desktop PC (and wish there was a way to disable it), within 45 seconds it freezes up the entire system...from what I'm experiencing if doesn't look like this version is stable on Windows 8.1 systems.

I don't think so, I can't even recall seeing an option like that. How can I tell if it's enabled or not ?

Recently Opera (21.0.1432.67) has been lagging lately....not just your average lag mind you but really badly, to the point where my entire system freezes up! and it doesn't stop, I literally have to force reboot my PC with the physical reboot key on the case each time it happens, and it doesn't happen all the time now...'eventually'. It only happens with Opera (and version 21 at that), I'm guessing that it's a memory leak maybe ? Anyway if anyone has any info that can help or have experienced something similar then please by all means....btw I'm running Windows 8.1 Enterprise 64bit.

@im5049,

Can you provide a screenshot of the error !

My user account shouldn't matter since I had successfully installed and run Opera before this.

Even if you had successfully installed & used Opera before, that doesn't change the fact that if your user account profile became corrupted, that it wont no longer work properly.

Are you one a 'Standard' account or an 'Administrator' account btw ? I ask because you said that you can't access the 'prefetch' directory, which is a bit strange. You should really try running Opera from another account, there is no harm in trying!

You may also want to run a check on your hard disk drive for errors or bad sectors, just to be on the safe side. You can even try a system restore to a previous restore point before you updated Opera and see if that helps.

@im5049,

Does the Opera browser work in any other account (preferably an administrator account)? If so, then your user account profile may be corrupted. If this is the case then at best, all you'll have to do is create a new user account & reconfigure any application that stored it's preferences & configuration settings in the user account folder (%homepath%).

On the other hand, like suggested above by linuxmint7, perhaps this is the result of a failed update which left some registry entries that is causing the problem. If this is what is happening then there are free uninstaller software that can help remove any leftover unwanted files and registry entries when you uninstall an application. You can even open the registry editor and try to find & remove them on your own by using the 'Find' option and searching for words like 'Opera'.

Another possibility is that the prefetch cache for the Opera application has become corrupted. This is unlikely but does happen on occasion (rarely). To remedy this situation, all you have to do is simply delete any file the contains the word 'Opera' from the prefetch folder located at 'c:/windows/prefetch'(%windir%/prefetch).

Hope you can figure out this problem to help others that may also face it.