[Jstylezzz]

You don't have to worry about sa-mp or GTA SA having a virus. This, offcourse, if you downloaded sa-mp from the official locations on the download page, and if you haven't pirated GTA SA. Crackers can stick all kinds of shit in cracks. I don't think other mods contain viruses, however, if they're installed with a separate installer, there could be unwanted things deployed on your computer. As AaronKillz said earlier, make a scan with malewarebytes to check if anything is infected. Before downloading mods, be sure to read the comments, if there's a virus inside it, people comment saying that, most of the time.

Good luck!