answered about 21 months ago by mrdx
There are lots of computer hardware shops in Hanoi (by lots, I mean thousands of them =D).
The first place you should go is Ly Nam De street aka "Computer street". There are about 50-ish computer stores there (but only go to the busiest-looking ones though, don't waste time on small shops)
To have an idea about prices, check some links I've found from Google, using the keyword "laptop cũ" or "máy tính cũ" (there are many more)
http://www.everest.com.vn/?category=200&op=product&language=english&task=listproduct
http://www.vn68.com.vn/vn68/?a=CATE&hdn_category=4
Btw if you don't speak Vietnamese, it'd be best to go with a Vietnamese friend. There are some luxurious computer centers that are more foreigner-friendly but I don't think you can find good deals there.