These are the errors that appear when I open Unity:
Assets/_CompletedAssets/Scripts/Helpers/RandomParticlePoint.cs(12,9): error CS0619: `UnityEngine.Component.particleSystem' is obsolete: `Property particleSystem has been deprecated. Use GetComponent<ParticleSystem>() instead. (UnityUpgradable)' Assets/_CompletedAssets/Scripts/Helpers/RandomParticlePoint.cs(12,24): error CS1061: Type `UnityEngine.Component' does not contain a definition for `Simulate' and no extension method `Simulate' of type `UnityEngine.Component' could be found (are you missing a using directive or an assembly reference?)
And when I put a script:
Please fix compile errors before creating new script components.
The first mistake is that you're using an old project, and you haven't converted it to work in Unity 5.
The second is similar, the difference is that it calls a method and doesn't find it.
When you answer which project you're trying to run, I'll explain what you need to do to make it work – if at all possible, as some very old projects are way out of date and the work to solve would not be plausible for a stackoverflow answer (but not should be the case, this error is common in version 4 projects which is newer).