You can buy a USB to SATA drive case for just a few dollars. Put the new SSD drive in it. Download a copy of Macrium Reflect for free. This is great disk cloning software.
Run the program and have it clone everything on your hard drive onto your SSD. Make all the partitions that same as before except that if you have more space, add it into the biggest partition. Don't worry if you mess it up, you can always clone again.
Now, put the SSD into your laptop. This site has reasonable pictures... you don't need to take much apart to install the drive.
https://www.ifixit.com/Guide/ThinkPad+T ... ment/78827
Now, boot it up. Should come right up and be much faster. If issues, put the old drive back in and figure out what happened.
Windows 10 - never free if Microsoft won't let you install it over Win 7 - get Pro if you are going to install, not Home.
Go to
https://www.microsoft.com/en-us/softwar ... /windows10. Download Win 10 and install. It will automatically handle all upgrades. If it won't work, it puts you back at Win 7. Will tell you if you are not eligible for a free upgrade. If not, go to Challenger and buy a copy.
Office never free. Do not buy Office 2016. Never ever gets new feature updates, only bug updates. Instead, subscribe to Office 365... yes, I know you hate to pay $99 per year... but you can share with 5 people and on multiple PC's, and you get all the updates and features. It's Microsoft's way of forcing you into the subscription model.
You can buy a decent $500 gig SSD on Amazon for USD 52.
https://www.amazon.com/Silicon-Power-Pe ... ref=sr_1_1
Trust me... this is not a hard thing to do if you read and follow instructions. Your laptop makes it easy to swap hard drives.