I think I broke something in my computer while trying to fix it, HELP!!!?

I think I broke something in my computer while trying to fix it, HELP!!!?

Ok, so as of a couple of days ago my pc would only turn on for about 5 seconds before shutting off. I looked online for solutions and read that I could try to reseat some of the components. So, last night I did that and only removed anything that came off easily. One of those two things were the two memory sticks inside, I’m guessing it was the ram, I removed a couple other cables one of them was a smal blue cable with six holes that connect to six prongs near the back of the computer. I honestly don’t know what it is, it connected to the usb slot on the front of the computer as well. Well, when I umplugged that cable, one of the prongs came off and is stuck in one of the holes. Also I’m not sure if the ram is seated correctly because now it comes off way too easily. So after I plugged everything back in… the computer worked and it did not shut off BUT it will not recognize anything
that’s plugged into it, monitor says no signal as well as mouse and keyboard don’t work. I tried plugging the keyboard into the usb port on the front but still nothing. So, does anyone have any idea as to what might be the problem, solution, and approximate cost? I don’t have much money and so dont want to take it to a repair service as they most likely will rip me off. Please, please,
please! Help!