Hey guys. I'm a beginner (playing just over a year) and I primarily play an epiphone les paul. Well, the other day, someone gave me a squier strat that looked to be in great shape. It sounds really good through the clean channel of my amp too. The problem comes when I step on my danelectro fab metal pedal and give it some gain.

The thing lets out a nasty and constant screech unless I am totally muting the strings. Now, I expect some sort of feedback or noise at high gain, but my les paul doesn't give me any trouble. So I think my problem is either with my pickups or the selector. Whenever I move, or even touch the selector, the sound sort of fades in and out. Long story short, I have no idea what is wrong, but am hoping I can bring it back to life.
It's probably crappy grounding, Someone didn't solder a squire strat right.. Not much of a suprise. Your Ephiphone Has humbuckers, the strat has 3 single coil's and thats alot diffrent. It can be your chord, the pedal, the amp, the guitar, the pickups, anything. Danelectro's 15 dollar bargain bin pedal's aren't anything special either bud. You need to throw that in your effects loop, or not use alot of gain, or get a noise suppreser, AE. noise gate. Hope that helps some..
I know my pedal sucks, but I got it when I first started. I have a new amp waiting for me when I get home from work today, so we'll see how things work with that. The problem with the selector is always there, if I touch it lightly on a downstroke, the amplification totally cuts out until I mess with the switch and bring it back.
Is replacing it a pretty easy process? I assume I just have to unscrew the pickguard area to get in there?