Toshiba Satellite L305 Power Issues

I bought this laptop used about 8 months ago. It has been a great laptop so far. Only issue I noticed with it physically is a loose socket where the power cord plugs into it. It was cleaned thoroughly before I bought it, inside and out, and I've never noticed a heating issue with it as I did with an antique laptop I had that finally fried.

But the laptop is used basically as a desktop, sitting in one place 99.9% of the time and continuously plugged in. And it has run wonderfully.

But, today, twice, for the first time since I got it, it has suddenly shut itself off. It just goes black, like someone pulled the plug, but the light indicating plugged in power remains on.

Nothing has been added to the laptop or removed from it physically. I haven't added any software to it for several weeks. But I'm concerned this is a sign of an upcoming problem and I'm looking for ideas on how I will need to fix it. Could this be a problem connected to that loose power cord socket?

I really need this laptop as it is my online job. No laptop, no income. And so I'm really hoping for some helpful suggestions here.

Thank you in advance.