Problems, problems, problems

I seem to be having trouble with my physgun and toolgun. My physgun can’t pick up NPCs, ragdolls, things spawned on the ground with the toolgun, or any of my entities. My toolgun won’t work on NPCs, ragdolls, entities ect. This hapened after I download TF2 NPCs, gm_wtf_5, and npc scene w/scene folder. After I started wtf_5, this was the first time I couldn’t pick up stuff. So I deleted all this crap (lua and everything about it), and it didn’t work. And Steam Support ain’t helping me. What can I do to fix this. And in case there isn’t anything I can do, how do I reinstall the game from scratch (without custom addons. maps ect, just HL2, Gmod maps, HL2 Ep1 & 2, Counter Strike: Source, TF2, Portal, and DoD maps)? I mean, like the way I saw it when I first bought it.

local tClasses = { "prop_physics", "func_physbox", "worldspawn" }
local function PhysgunPickup( _, eEntity )
    if ( !table.HasValue( tClasses, eEntity:GetClass() ) ) then
        return false
local function CanTool( _, tTrace )
    return PhysgunPickup( nil, tTrace.Entity )
hook.Add( "PhysgunPickup", "gm_wtf_5", PhysgunPickup )
hook.Add( "CanTool", "gm_wtf_5", CanTool ) 

Found this in the lua folder I got when I downloaded that map.
It looks like it makes you unable to pick up said entities.
Remove this lua file and restart Gmod and everything will work.

This is what the readme says:

thx ill see if it works. You now get a chance to DINE IN HELL in SPARTA!!!