Usually when the computer hangs, it's because of the RAM memory usage, but for my case my com hangs because of the CPU usage.
Affected applications including streaming Youtube HD videos, certain Facebook games such as Pet Society & Crazy Planets, video-chat etc. The com will lags while running those mentioned applications.
I noticed the lag this week, after unable to run a Youtube HD video smoothly. Later on when the problem gets kinda out of control, I've decided to reformat the computer to clear it all.
Woke up around 7am in the morning. It wasn't a good sleep as I was disturbed by someone outside there. Anyway good to wake up early to proceed with the plan.
Spent 2 hours backing up things and tried some alternatives before reformatting. Windows System Restore looks useful but unfortunately it couldn't solve my problem.
Reformat starts at 9:13am. It finished installation within an hour's time. Everything's running smoothly without any error message.
Windows are done around 10:15am. Proceeded with installing the drivers before I can get the computer running like normal. Good thing Dell includes the Resources disc for reinstallation purpose, very handy. It took awhile to install all the drivers and after rebooting the computer it's almost done.
Next step is to install the usual programs I'm running, namely web browsers (Chrome & Firefox), Windows Live Suite, and some photo-related programs (Picasa & Flickr Uploadr). Windows Update is running at the same time.
Well then, until now everything's running well, which I'm quite happy bout it. Been spending almost the entire morning to fix it.
One thing I noticed about reinstalling Windows, is that the old files and folders will be automatically backuped even when reinstalling Windows at the same drive (by default, C drive). It would throw everything into a directory like this "C:\Windows.old". Anyhow it's still good that if you can backup another copy to an external HDD or burn it into a DVD, just in case anything happens.
Theoretically I know how to reformat, but this is actually the first time I do it on my own lol.... because usually I would be reluctant to mess with my large quantities of data and programs. Reformat might be troublesome, but it's useful when you need to start things afresh.