JaariAtmc

Yeah, allocate more than 1 GB for a 1.7.10 modpack. Launcher Options > Java Settings > RAM selection dropdown. 3 GB should be plenty for most 1.7.10 modpacks. Can't allocate more than 1 GB? Download the offline windows java installer from the java site.

Dead pixelmon modpack, try one of the gazillion others.

Well, you download minecraft vanilla, you open the minecraft.jar with 7zip or winrar, and then you add a modloader. Then you start minecraft. You close it again, you add 1 mod. Start minecraft again. Close minecraft. Add another modpack. Start minecraft again. Rinse Repeat. After about 10 mods, you will find that it doesn't start anymore. You'll have to start over, by adding all the mods in a different order. Good luck getting a 20 mods modpack. Those took forever. Guess why we're so happy with MinecraftForge.

Below 1.2.5? Ah, you want to get started with the lovely wonders of minecraft.jar editting huh?

You changed the dropbox URL. Did it work on the new download you made? Otherwise, "which" forge are you using?

Black particles? That's a Biomes o' Plenty mob, and its invisible, if it weren't for the particles. Just hit the black particles.

Yeah, don't do that, that doesn't work past 1.13 anymore. Download the installer jar and rename it to modpack.jar.

Did you rename the universal.jar or the installer.jar? For 1.13 and above, you need to rename the installer.

Downgrade java to 8u25/8u45/8u51.

Sounds like you are playing TekkitMain, or Tekkit Space, which is for 1.6.4. Tekkit Classic is for 1.2.3/1.2.5. So yes, looking at tekkit classic videos is going to be a bit of a mismatch yes.

Oh yeah. The only problem, no one will ever read this. Other places you can find this information is the News Tab on the Launcher.

Yeah, remove java 14, install java 8.

Like, have you tried updating the video card drivers? If yes and still not working, try downgrading java to 8u25/8u51.

Yeah, that's indeed a modpack that would probably work on MultiMC. Point is, the required file structure for MultiMC is different. Please follow the modpack creation guide (valid up to Forge 2847 for 1.12.2, higher not supported) here: https://technicpack.zendesk.com/hc/en-us/articles/204199345-How-to-make-a-Minecraft-modpack

Is this a server? Or is this a modpack? What is spongeforge doing in this modpack? Spongeforge is server software. Resourceloader for example is incompatible with spongeforge, as Resourceloader is a client-side only mod.

Purely based on the size of the modpack.jar, use Forge 2847, not the 2854 you are currently using. It won't work.

Don't use 2852, use 2847.

This is what happens if you download half your mods off 9mc. Only download from Curseforge, and check all required dependencies.

Have you considered reading the crash message? Have you compared said crash message to the top of your mods list?

2854 uses a wholly different installation mechanism which is currently not supported by this launcher. Based on current progress, it will likely be compatible soon-ish.

Have both of you ever used MCleaks? And what antivirus are you two running?

Add NotEnoughIds to your modpack.

Ya, downgrade your java to 8u51 or 8u25. Vanilla minecraft launcher uses its own bundled 8u51.

Open the server saves folder, locate the DimDoors folder and delete this folder. Start the server again. This is a common issue for tekkit when a computer is suddenly shutdown, either by crashing or by power brown-/blackout.

There are still loads of players with IPv4 addresses.