Sorry... its a bit confusing. 5amps at 250v power adaptor is quite big even for a gaming laptop.
Laptops usually comes with its own AC-DC power adapter. These power adapters are usually auto-volt & should be usable in any country ( by the way, Hong Kong is 220V 50Hz). If you will use the same power adaptor that came with your laptop when you purchases it, it should not explode.
The rating of the power adaptor is expressed as:
Input : Usually 110/220Vac @ ?? Amperes 50/60Hz
Output: ?? Vdc @ ?? Amperes.
Please check the markings on the power adaptor & see if it supports 220V. In this case, you should be okay.
Depending on where you are coming from, you may need an adapter. The Hongkong AC socket is like in Malaysia, Singapore & the UK.
Like this: http://electricaloutlet.org/type-g