What happened to my computer? It won’t start at all?

My computer run or start at all, and it had been having some problems for quite a while.

AOL 4 in windows 98 stopped working back in 2018 forcing me to come up with some weird way of getting online. My “whiz kid” neighbor set me up with a new system running windows ME which wasn’t very hard to learn and was similar to 98 and just had to get used to explorer and outlook 2000 and and told me to set up DSL and helped me plug a strange box into the computer.

This new system worked better for a while and then it started having MAJOR problems. The system started popping up pictures of breasts and all kinds of inappropriate click bait.

It also gained a program that was supposed to remove malware. My files started to disappear and a folder named OUTVID.16 appeared on my desktop.

The dial up modem would randomly dial and have muffled voices being heard from the computer

Eventually the computer was running when it’s hum stopped and then it smelled weird and puffed out smoke and quit working.

What could have happened? How much might it cost to fix?