Why won't cydia show up on my iphone 3?

I bought a iphone 3 a long time ago i factory unlocked it an jailbroken it an cydia showed up but then a couple months later it was gone i had this phone for a very long time an would love to get cydia back

This happened to me but on my old ipod 4th gen, found out the only way to fix it was to restore it and re-jailbreak it

  • Why won't the facebook icon on my iphone show up? I downloaded facebook on my iphone 4s, it says "installed" and everything, but an app icon never appeared for it. When i go to the app store, next to the facebook app it just says "OPEN" so i can't re-install it and the only place i can access it. Can someone tell me how to make the icon show up please?
  • Why won't my iphone show up on my computer when i connect it? I connect my iphone to my windows laptop with a cabel thingy and it shows up that its charging on my iphone but it doesn't give me any options to transfer media etc. Also when i go on 'computer' it doesn't show up even though it should because its connected?
  • Why won't my iphone show up on itunes? I have the old ITunes, I haven't had a chance to update yet. I just downloaded some songs and want to put them onto my iPhone 5. I have never had this problem before, but my iPhone is plugged in and shows up on my documents on the computer, but I can't get it to come up on iTunes? Any Ideas?
  • Why won't my iPhone show up when I plug it into the laptop? Okay, so I was trying to edit a photo on a website which meant I had to plug my iPhone into the laptop the get the photo up. I've done it before, but when I tried it the second time, my phone won't show up when I plug it in? ITunes is working fine and everything though. So what do I do?