Old car won't turn (start)?

My name is Michael. I was released from hospital about 7 months ago and was told I was not allowed to drive for 6 months following the operation.
My car, a 2005 Ford Focus was just sitting at home that whole time.
Now, when I turn the key there's no "dead battery sound" where the car can't fully start but there's no sound, movement or anything of the sort when I turn the key.

I don't really want to pay a mechanic to fix this as I'm pretty sure it's just a problem with the battery. Are there any ways to sort this out myself relatively cheap and easy?

You have a completely dead battery, not a low battery which causes the sounds you were trying to describe. While it might take a charge, I'd just go buy a brand new battery. Be sure you thoroughly clean and tighten the cable clamps and always connect and disconnect the ground (negative terminal) cable first. It's not rocket science. You might also need to drain the fuel tank, replace the fuel filter and add fresh gasoline. Sitting that long it can easily go bad, especially in hot weather. All automotive gasoline has a "shelf-life" unless a stabilizer is added to it. You'll know when you install the new battery. If it cranks over, and keeps cranking without starting, you'll know.

The battery is likely dead. Remove it, get it charged and load tested at a battery shop. Replace if it fails the load test.

Your batts dead. And your gas is spoiling… Gas has a life of about 6-9 months… So be wise to that mess…

Wouldn't worry too much about the fuel but go buy a new battery. (Biggest problem with old fuel is that the mix is different summer to winter & you've gone from Spring to Autumn so almost certainly OK.) By the time it's a year old, yes there's often a problem.

Batteries die if not in use. Yours is dead as a Dodo, New battery should fix the problem. Forget the rubbish about bad fuel. Unless it's been subjected to exceptionally high tropical temperatures it should be fine. My petrol mower starts first time having been stood for almost a year.

Charge the battery. Probably an overnight job after
6 months standing, but you might just get some charge in it. If that doesn't do it, then it's time for a new battery, which you might need pretty soon anyway. If the car cranks but doesn't start a squirt of a diesel easy start spray in the air intake works wonders (don't do this too often)
Please check the tyres before driving, and test the brakes as soon as it moves. There will be a lot of rust to scrub off the disks. First move may be difficult as the pads are probably stuck to the disks; the brakes will be rough for a few goes, but should improve with use

Hook the battery up to a charger and let it run for a day or two before you try to start it again. If the car STILL doesn't start, it's time for a new battery.

Clean the battery posts and cable clamps.
Charge the battery with a portable battery charger set to 12 volts, 10 amps, for 6 hours.
A completely dead battery won't even make the starter solenoid click!

Battery is as dead as a doorknob. You could try jump starting it or charging it, but it's probably beyond saving and should be replaced.

Jump start the car and drive about 10 miles, then come home. You would do good to own a portable rechargeable booster.