1) My computer is really old and very full, how much space will Minecraft
take up in my computer ?
2) What graphics chips are best ?
3) My computer is a early model vista and it runs slow so will Minecraft even
be able to run in general ?
4) Will I have to pay monthly/weekly/etc for online ?
5) Will I get a icon on my desktop or do I have to be online to play ?
P.S. Sorry I am very computer challenged and need a lot of help. Thank you for any and all help.
There's a helpful page at Minecraft Support that lists the recommended and minimum system requirements to play Minecraft.
You don't need to pay any monthly subscription fees to play regular Minecraft. If you want to play on a multiplayer server, that may incur fees - each server is run by someone different and they have different payment policies. But a single person playing Minecraft on their computer by themselves (or with other players in their own house) will never need to pay any ongoing monthly fees. Once you've purchased Minecraft, all future updates will also be free.
No you don't need to be online to play. You will get an icon on your desktop and if your computer is connected to the internet, Minecraft will check for updates as it loads. But it doesn't need you to have an internet connection unless you want to play with other players in a multiplayer game.
I hope this has cleared up a few things for you. I know that it can be difficult to understand sometimes, so please feel free to write anytime with questions!