decompression error, archive is corrupted error code 7 decompression failed

Hello. I bought a computer half a year ago, but somehow during this time I had enough games on the old hard and I usually buy games. However, there was a problem during which I came to the conclusion that maybe a broken operative or hard. Everything described below has never happened to me on other computer configurations.

In general, I downloaded the game from the torrent, the first problem that overtook me was the download stopped at 99.9%, then I could wait for hours, but the download did not happen to the end. Then I google it, they say, put another client of the tracker. put another one, rehashed the game and, having finished the last percent, got out a blue screen. I did not have time to remember anything because the computer went into reboot. This topic did not make me happy. I started downloading the same game from other sites, but all the repacks were stuck at a 99.9% jump. In the end, I found a repack that worked to the end. But during the installation, it gave an error saying the archive is corrupted, the error code blablabla .. I downloaded from three different distributions, but during installation it gave the same thing. Then I decided to check what if I zip it myself and try to unpack it. I zipped the first season of the series in SFX, that is. so that the archive is exe. and to my surprise, when unpacking my own archive, I was told that the checksum does not match blablabla. Well that is that the archive is damaged. I googled half a day but did not find a way out of the situation. There were options like copying missing files to the Windows folder and other crap. I did not rearrange the operating system, given that on many sites for people with a similar problem, this action did not help. The main reason is basically a broken RAM. So my question arose as to how this is actually connected. And if the computer itself sees the operative in full (I have two 8GB boards) in games there are no problems, but only when installing repacks, then what actually happened for the garbage? How to win this, if someone had such problems, how to solve them.