What does freedos actually mean sorry noobie here >.>

Sorry that you have to went through all that. But I'm glad to know that you didn't fell for their tricks
Do take note that the Vostro 5460 has a pretty weak WiFi card ya, will be a problem if the router is far away.
Though there was a case that a customer managed to ask Dell to replace it with a Realtek WiFi card which solved the problem instantly

Yeah, some of the sifus here are really, really pro 

Yeah, just one at the moment. I'm helping my friend to "fix" hers as well
Will update if it works~

Otherwise, perhaps can consider the 5470? Or perhaps other brands? 

i am wondering if 6 cell battery offer longer battery life than 4 cell?

thanks for your recommendations, but i found difficulties after you recommendations, that is i can't found any review about the laptops and even tech specs of lenovo models~  even though i found it in the computer shop, but no brochure for reference too. what can i do if i want to do comparisons for these laptops?

would you recommend Lenovo Z400 touch, Z500 touch, G400s and Z480 for my usage? since these models are still within my budget. thanks.

Lightweight (< 1.6kg) and detachable battery normally don't come together for new models 
Need to find some old design 11", eg:

Lenovo
ThinkPad Edge E120, i3-2357UM + Intel HD3000@RM1999[1.5kg],W7HP, water resistant keyboard

Forget about detachable battery lah. With your usage, unless the laptop really has lousy thermal design, it will not heat up much. And no matter what you do, Li-ion battery probably will give you 3 years of service anyway

it will be RM200 if im not mistaken.

for warranty void part, doesn't apply if you take care of the part removal process. even the technicians also dont know that you did opened up the unit if you do it carefully.

slim Li-Ion batteries are very expensive. thats why you cant argue over that. with a laptop weigh less than 1.6kg, none of them has a battery latch for user replaceable batteries (especially ultrabooks). so normally I will suggest peoples to provide good ventilation for their laptop (heat is an enemy to Li-Ion batteries) and most importantly, dont use the battery less than 30% of the battery gauge. Li-Ion batteries are subjected to wear and tear, so to avoid costly battery replacements, it is better to take care of batteries rather than have availability to replace it.