Well, I am pretty sure that I have encountered spirits

Alright here we go. My ghost story. 100% satisfaction guaranteed. The only person who I told this on here is IB. Catch up people.
This took place years ago, when I was in my old home and I had just bought a new webcam to use over msn. So I was talking to people with it on and when I'd say brb. The people I was talking to were like hey did your dad come in here while you were gone? And I'm like nope. Other times they would say, hey is that your sister that just walked by? I looked around and so I finally asked why and the girl I was talking to said they thought they saw someone walk by. Again later, I was in the computer room and once again the girl said someone walked by. At this point I was nervous but still unconvinced. I was the only person in the house near the computer and the door slams shut. I became quite afraid and assume some windows were open. Even if they were how could that door slam shut? It had a mini basketball net attached to it and it was almost impossible to close right. So still I'm like pft whatever its just random **** happening. So I open the door back in and the girl I'm talking to types in capitals that someone is behind me. I look in the picture of me of in the webcam and see a green figure leaning against the door behind me. I instantly sweat and turn around at the speed of light just to see blackness, no figure. I glare back into the pic and a very clear green female figure is in the camera leaning against the door. So I instantly turn the camera off and tell myself that if was a ghost why the hell is it only in the camera? It must be static or something because years ago the camera was new, but it was still a piece of crap. It must've just been a blur of some sort.
This is the part that scared the **** out of me. One day I walk into the basement and hear a harmonica playing. I tell the air to not hurt me and I slowly crept to the stairs and booked it. A couple more visits of the harmonica I tell my sister. She hears it too. So one day I brought my friend over and we were playing Soul Calibur 2. Lol I have Soul Calibur 4 now. Anyway the harmonica comes on and I'm like dude do you hear that? And hes like yeah dude its your screensaver look. I look and see a picture of a girl with a harmonica in her hand. Totally relieved I switched screensaver.
However this is where my hallunications come in.
One day I went on my porch and I was expecting my sister to come home from her friends house anytime. So I'm on the porch. Lots of voices in my neighbourhood, the neighbours have a pool and kids are always there. So suddenly I hear my sisters voice saying David, open the door. Naturally I ignore and I looked over and didn't see anyone so I believed it was just me intrepreting the voices to be that. After a few more calls I reply
What? Just knock, mom and dad are home. She says just open the door. I don't answer
David! Open the door. So frustrated I say oh my god fine and stomp to the front door and swinging it open a skeleton popped out