No idea what hardware you have right now (motherboard type/chipset) but if you still use an old style (rotating platters) harddisk, replace it with an SSD. I'm pretty sure you'd be in for a shock !
I still got an old 2010 15" MacBook Pro and although the SSD disk can't use the entire bandwith of the SATA controller (SATA2, not SATA3 speed) it still gives a speed boost, 280MB/s instead of 440MB/s. You will notice that.

Not as fast as the newer PCI-Express x4 disks as my 2015 13" MacBook Pro has but performance is not bad, not bad at all.
Get a Samsung 850/860 EVO, cheap, reliable, fast. It's the only brand I use for my PC's.
If you don't want to reinstall your operating system from scratch then Macrium Reflect (free edition) does a solid job in cloning your old harddisk to an SSD from within Windows. There are other tools as well, it's up to you.