Okay, so I recently had some malware on my computer and I removed it all. Minecraft was lagging when I had the malware on it. I got the malware off, and it still lagged. I set the render distance to tiny, set fast graphics, and took off smooth lighting. It helped a little, but it still lags a little, I don't know if it is possible to remove All lag, but i don't know what else to do. I have an old computer, a dell laptop and i recently updated it to windows 10. I don't know what a graphic card is, and i would also like to know how to find it on/in my computer if it even has one. All answers appreciated, thanks.
p.s. I won't be able to get any kind of desktop setup anytime soon.
Added (1). Note: I don't know if this changes anything, but I bought Minecraft from the official Mojang website using a gift card. Also, is there a way to change your username, because mine is so stupid, I hate it.