Microsoft publishes its end-of-support schedules well in advance. to stay both current and safe, it would be wise to plan for that turnover.
Replacing a hard drive on an identical model laptop might just work, but let’s make sure there are no misunderstandings here.
Moving data to your new machine from your backup is easy. Moving the programs is a different story.
Unfortunately, the full solution to this problem can be quite painful. We’ll start with some easier fixes.
You may want to switch to 64-bit just for the speed that comes from being able to use all of the RAM on your computer. Ultimately, it comes down to what you use your machine for and your own time and resources.
Windows 8.1 should respond to some of the issues that people expressed having with Windows 8, though not all of them. Your choice of how, when and what to upgrade may have more to do with hardware than with software versions.