I'm a former computer tech. I'm here to help.
First of all, of the three brands you've posted, Toshiba is enjoying the best reputation for quality, and HP is the worst. In fact, HP has very little respect for quality amongst people who repair computers.
Gateway is actually an Acer budget brand. Acer has a good reputation for quality, but the budget computers from any computer company (which all of these computers are) will always be of poorer quality (components, construction, and design) than their regular notebooks.
Of the three you posted, the HP is the slowest, followed by the Toshiba, and the Gateway is probably the most capable.
That being said, none of these computers will probably be very much good to you for real world application. You get what you pay for. All three have entry level graphics adapters, but all three graphic adapters will share the main memory of your computer, so none of them will be great gaming machines. The Gateway probably has the weakest graphics adapter of the three. (FYI graphic adapter is a co-processor that is dedicated to running on screen graphics, so the better it is, the less your actual computer has to work, and the faster it will appear to run).
In the end, I would go for the one with the best warranty. Apart from what I listed above, the rest of the components are equally bad.
