Finally, my computer is running again.

I was surprised at the monthly bill from Emory. The 2.5 months housing bill added up to this month and surpassed my monthly income. And to make things worse, my computer was crashing from time to time after I did some modification to the partitions. Then I thought that maybe my BenQ Joybook was too old to accompany me any more and I need to get a new computer. But the financial burden I'm facing has made it very difficult. So I decided to give a last shot before taking on more balance in my credit card.

I first used "free" command in terminal and discovered that the swap has size zero. How stupid! Some modification may have disabled the system from automatically mounting swap partition. Then I swapon'ed using partition manager of ubuntu (qparted).

To completely solve this problem I googled "ubuntu auto swapon" and come into this website:

https://answers.launchpad.net/ubuntu/+question/34437.

Then I realized that it is the UUID problem. So I edited fstab according to the output of blkid.

Finally I rebooted. Now it's running OK again. :)