However, it's more likely that the charging components are failing. Take the laptop to a local PC repair shop and ask them to order suitable replacement parts. As your PC warms up, a component or area of motherboard solder may be expanding to the extent that it breaks a connection.
Tips to Fix Laptop Power Supply Problems
First, turn off your PC and disconnect it from the mains. Earth yourself by touching something metal, such as a radiator, and then open the case. Remove and reseat each component in turn, ensuring that all components are replaced and cables are reconnected correctly.
Also, make sure that all connected devices are firmly seated in their ports; if you've been fiddling with the insides of your PC you'll want to make sure a RAM chip or video card hasn't come unseated. Ideally, you'll be able to figure out which component of your PC is acting up; this would make the call process much easier because the phone tech won't be able to refer you to another company because it's a problem with that third party's product, not with theirs.
And if your machine continues to shut down without warning, take it to a local PC repair shop - it may require a new motherboard or another component. Here's how you can streamline the tech support process and make sure you get the fixes you need.
Another way, if you can, start by figuring out for yourself exactly what isn't working. The more details you can put together about what part of your computer isn't working, the better - especially if you have a smartphone or an extra computer handy that you can use to plug those details into Google. Chances are, any problem you have with a piece of technology is one that someone else has had as well, and if you're lucky, they've posted extensively about it on a forum or company's support site.
Also, don't forget to keep your stress level low while you're troubleshooting. You should also perform a few basic tests yourself: reboot into Safe Mode and see if the problems persist, and try booting from a recovery disc and run Windows' included diagnostic tools to check the state of your hard drives, RAM and system install.
Generally speaking, if you weren't able to fix the problem with Windows' built-in diagnostic tools, the first-level techs aren't going to be able to fix it by asking you to reboot or reinstall Windows, and you're probably calling tech support because your problem is so bad that you need someone to authorize a warranty replacement part.