I have 100$ to spend on upgrades to my PC. What could I get to

You will need far more than that.

While I can't see your GPU, both your CPU and RAM is severely outdated for anything except light browsing. If you want to do stuff like edit at some level or play somewhat demanding games save up at least 500$.

>>17688536
get a new windows

Probably going to want minimally 4 gigs of RAM, 8 is pretty standard now but 4 will probably let you run on low/mid settings. If you get a better cpu (i3 or i5 tier) you can probably forego an independent gpu if you're running on lower settings

Mind you, I have no idea if your current hardware will support those upgrades, so you might want to save up for an overhaul or replacement

Get a dedicated soundcard, it will offload all the sound processing from your CPU.

Seeing as your CPU has to do literally many thousands of calculations every second to pump out sound, getting a soundcard should bump your fps by about 40%. My fps in CS:Go went from 60 to 100fps after I did it

>>17688536
Find used B75/B85/B150-socket motherboards, compatible CPU and RAM. Would be better to expand your budget to the 200$ point.

Throw away the shit you have and look up a guide on a decent 500-600 build. There is nothing you can do for 100 to fix that. FIrst of all your shitty OEM power supply unit won't support a new video card. Secondly our processor is outdated. Get a i5, and at bare minimum a GTX 1050, although I highly recommend a GTX 1060 instead it's well worth it.