I suggest doing it this way:
1. Get a 2.5" SATA SSD (size of your choice). DON'T buy "the fastest". BUY FOR PRICE. I suggest Crucial or Sandisk.
2. Get a 2.5" USB3 SATA enclosure. Cheap and many choices.
3. Download CarbonCopyCloner from here:
www.bombich.com
CCC is FREE to download and use for 30 days. "Doing things my way" costs you nothing.
4. Put the SSD into the enclosure and use disk utility to erase it to Mac OS extended with journaling enabled, GUID partition format.
(You didn't tell us which version of the OS is on the drive you have)
5. Now open CCC and use it to clone the contents of the internal drive to the new SSD. So easy that a child can do it.
If CCC asks if you wish to clone over the recovery partition, YES, do this too.
6. When done, TEST THE CLONE. Power down, all the way off. Press the power-on button and IMMEDIATELY hold down the option key, and KEEP HOLDING IT DOWN until the startup manager appears. You should now see the external SSD as a bootable option. Click on it with the pointer and hit return.
7. Do you get a good boot?
8. If you do, NOW it's time to power off again, then open up the back and switch drives.
9. Once the new SSD is inside, AGAIN boot up using the "option key trick" described above.
10. When you get to the finder, open the startup disk preference pane and reset the SSD to be "the new boot drive".
That should do it.
I think all the Apple apps will work.
Can't say for certain re MS Word. If it works, it works. But keep in mind that if you did this any other way, you'd probably get the same result.
You'll just have to try it and see.
Once you have the old HDD "in hand", you can put it into the enclosure, and use it as a backup drive.
