Number Pad not working
http://ubuntuforums.org/showpost.php?p=4444700&postcount=5

To fix it on Hardy (If you have the problem) :
Go to :
1) System
2) Preferences
3) Keyboard (Tab: Mouse Keys)
4) Uncheck (Allow to control pointer using the keyboard).
This should fix the problem....!!

Hosting multiple websites with Apache2 (with help of two utility commands a2ensite and a2dissite)
http://www.debian-administration.org/articles/412

Finally, I managed to figure out the problem of playing yahoo movie in Firefox on the lastest Ubuntu 9.04.
The symptom is:
I had already had mozilia-mplayer and vlc installed. Youtube can work smoothly. But somehow, the Yahoo movie failed to show me her pretty theatrical trailers.

I search around for days in google, tried everything I can see that might be helpful, but failed to have the yahoo movie work!
By chance, I right clicked on a flash that runs abnormally on yahoo(just appear for a second then disappear), selected About, I learned that the default SWF player firefox is using is Swfdec. So, I uninstal Swfdec-mozilla, and install flashplugin-installer(by Adobe), then...
WoW... Yahoo movie comes back to life!

Well, here is my conclusion, before, I already tried all kinds of flash plugins, including flashplugin-installer(by Adobe). But yahoo movie still can't work, now I've learnt that this is becuase the default flash player is still there even though I installed other flash players. So, once I remove the default flash player for firefox THEN install a new one, firefox finally got a chance to run the newly installed flash plugin.

机器第三次返修之后（上一篇blog写的是第二次），机器还是老问题，根本就没解决，只是把系统重新安装而已。本来还是满怀信心的，结果.....，实在是很敷衍。我又一次打电话给他们，实在是很无奈。客服在知道三次返修不好的情况下，将问题提升等级，告诉了经理。过了几个小时，经理打电话给我，我跟他重新讲述这个问题。他表示很震惊，最后的结果是重新修，如果修不好就给一台新的。他很快发了个快递的箱子，一天就到，速度很赞。紧接着送去维修之后，修了2天多返回来了。这次终于修好了，换了一根内存。
希望这机器能撑的久一点！

总结：从6月底到8月中，一个半月的时间内“入厂”4次，终于把问题彻底解决。真是佩服HP的质量，更赞他们这么有效率的Warranty.
经验是，跟客服打交道要有耐心，态度要坚决且鲜明（该是他们的问题，绝对不放过！）