Hello,\r\n

Leon,
Yes, most HDs will fit your machine. But when you order it, be sure you ask the salesperson to ensure it will fit.
Now, you know that the HD will usually come without anything on it. Blank. You will have to format it, then install whatever operating system you wish to use.
Take it slowly and do it carefully and all should work out well. Prepare for about a three hour project, to get up and running, then the next steps should be slow, too.
Once you're up, go to Microsoft's update site and update your OS to what is most recent.
Then install Office, or whatever apps you want, and then update them, too.
And at then end, install your anti-virus. The reason being that a lot of applications will tell you to disable AV before installation, so you don't want to go through that all the time, and you install AV at the end point.
-a.