The computer becomes extremely sluggish during gameplay or when exiting the game.
The computer becomes extremely sluggish during gameplay or when exiting the game.
I never mocked your system, I just stated that it's barely able to run the games that you are throwing at it and you are here looking for a solution which there isn't any unfortunately, since you cannot spend any more money on this system then this is what you have to deal with, and that's fine but maybe lower your expectations of what your PC can handle Windows 8.1 already defragments your hard drive periodically automatically, I don't think it's why you're experiencing lag, I'm sure your CPU would be pegged at 100% and that is what's slowing down your system and/or multitasking
I think the best option for you is a hard drive priced under 500 Brazilian reais.
Sorry, I didn't intend to criticize your system. The issue is mainly due to its outdated hardware. Check if you can afford a 250GB SSD to run Windows and popular games. If not, there isn't a straightforward fix. A clean Windows installation might improve performance temporarily, but it will eventually slow again. Uninstall unnecessary programs and close all background apps before playing a game.
SSHDs are no longer a suitable middle ground between HDDs and SSDs. They function more like HDDs with quicker read speeds for certain small tasks. Expanding capacity won't make much difference if it isn't needed for additional programs. I'd check what older or lighter games fit your current setup. Titles such as League of Legends, World of Warcraft (I'm not sure about that one), TF2, possibly CS:GO (it really thrives on 60+ FPS), and the original DOOM (free since it's open source, still enjoyable) would work. Basically, any game from the Xbox 360 era could be a good option. Your graphics card is outdated, but it shouldn't be your main focus.