Can I upgrade the hard drive on laptop

Yeah, you can always upgrade hard-disk in your laptop. There are so many hard disk available in market. Below is one of the link : http://www.memorysuppliers.com/laphardrivgu.html

Ya sure the hard disk of a laptop can easily be upgraded.But the hard disks of laptop and desktop are different. You can do it yourself as the hard disk is located at the bottom of the laptop,open the cover and remove the old one and fit in the new one. The easiest way will be to buy an external hard disk as you can easily use it.

i think its possible

Try visit some computer stores. Most of them have their in-house technicians who can advise you and assist you on what to do. If you can try avoid doing it yourself, much better, because by doing it yourself, you might risk damaging some parts of it. Better seek the help of the professionals trained on doing that task.

sure you can but check the warranty of your sis' laptop first. otherwise of you do some tweaking with it and unknowingly remove that sticker thing, the manufactures or store where you guys bought won't allow you for a freebie when the need arises. it's like changing a desktop's HDD. it's simple but the HDD of a laptop is more expensive than a desktop's. why go all the trouble when you can just buy an external drive?

You can always upgrade you hard disk on your laptop after it is also a comp so you can surely do it.