I would like to try to install a mod of cs 2 on the old version of cs 1.6. Tell me what requirements should be on the PC to play comfortably without lags? Maybe there is someone who can help me?

Why don't you just want to play the original version of cs 2? I can't tell you exactly what the requirements are, but I know for sure that computers even older than ten years, in principle, cope well with the mod. You can download it from this link https://all-cs.ru/cs16/sborki/cs-1-6-cs2-mod.html . Take a closer look at the site itself, maybe you'll find something. By the way, there are also updated textures for maps like Dust, it looks very cool and rich. I hope you'll be able to play and share your impressions with us.