Why does my internet turn off randomly and how do I fix it?

There's not really a certain amount time that it works for before disconnecting, it just does it randomly. When I restart the computer it works again, but it's really inconvenient sometimes and I'd like to know what's wrong with it and how I can fix it.

Automatically you internet is disconnecting it means that there might be number of reasons for this problem. You need to check with your cable connection whether it is inserted correctly or not and you might need to know lan card has the latest drivers installed in OS, drivers also matters here. May be your system is infected with some kind of viruses or trojans and better install a good antivirus programme as well.

If your PC is infected with virus install good internet security, if you cant afford one download a trial version of your softwares.

Check for the latest drivers according to your motherboard find them from yout motherboard manufacturer's site download and install them.