If your computer is slowing down, the first thing you do is bring up the Task Manager. This will give you a list of the processes currently running, and you can quickly spot any that are using high amounts of %cpu power. On my WinXP I hit control/alt/delete and it pops up. You can also do that in Windows 10. And here are some other ways to bring Task Manager up...
https://www.isunshare.com/windows-10/9-ways-to-open-task-manager-in-windows-10.html
The process names won't always make sense to you, but if you see one that is using 30-90% of the %cpu all the time, google it and find out what it's related to.
If your computer has a built in graphics chip, as it seems, those are always slower than good quality dedicated graphics cards. Graphics cards are usually very easy to install, and you can buy used ones on eBay for cheap (I've done this many times). But you need to identify your computer so you know which graphics cards will work for you. Does your computer have a brand name, a model number? What kind of cpu? How much memory? List them here. If you have a no name computer, try a free software like PC Wizard which will show lists of all the computer components.
Go to a website like TomsHardware.com, look in the forum section, then the graphics cards section...there are many people who would love to help you out with your graphics cards questions. But you need to know what kind of computer you have, and the cpu etc... or they will be flying blind.
This is easy stuff, educate yourself and then if you want to pay someone to do it for you, at least you will know what they are doing to your computer.