I would like to disable any unnecessary items in my startup folder. I found this folder to be locked, but I can defeat this. Will I disable the system by deleting anything in the startup folder?

G4 Quicksilver, dual 1 GHz, OS 10.4.11, no network, no periferrals other than internal SCSI drive and Firewire audio interface.
In short, this Mac does NOTHING but audio.

Hello

First, where is your folder ? If it's in the system folder, just don't touch it.
Can you list the items there is in it? I don't have a 10.4.11 anymore so I can't be sure what's leggit or not.

Note that almost everything that is in the system that you don't use, won't eat CPU at all. The best way to verify it is to use the "top" command in the Terminal app. It'll list all the processes with the memory used and the CPU %. Note that if you don't use some code loaded by the system, it'll end up in the swap file of the virtual memory, so freeing any RAM you would like to use.

One thing you can do is to switch off all services eventually open in the sharing prefpanel. As switch off the firewall if you're not networked in any way. Still in the network, if you happen to have some connection, use a static IP, it'll limit requests other the network.

The good side of OS X is, as I said, usually, any code you don't use won't eat CPU or RAM.
The bad side, is that suppressing any part or service is really rocket science. So the best thing is not to install any thing you won't need for the job, for example: other languages, printer drivers. (Though it'll mainly free some real estate on the hard drive.)