Hack

So, I got a new PC (better than my previous one) and I installed gta v through steam. Well it basically copied the files from one PC to the other. This includes scripthook and trainers/mods. On the original PC these mods and tools still work but on the new one scripthook wont even run. Any ideas what it is?

You have old version for the script hook ? ?

Updated scripthookV, scripthookdotnet.dll, and scripthookmetagen.dll. None of which seemed to work

"scripthookmetagen.dll"? That doesn't sound familiar.

OK; so you got a "new" PC. I'm pretty sure that means you lack the Microsoft Visual Studio Redistributables needed to run the mods. Your scripthook might work correctly but without the Reditribs, you won't be able to run the mods.

Is your Pc an x32 or x64? (Stupid question but just being thorough)
Look for the 2015 Redistribs and find out what redistribs were needed from the mods you installed. That info. is usually there in the READMEs or on the download section of the mod.