How can I uninstall Skype?

I changed from windows to a mac about 18 months ago and I can't beleive the difficulties I have had.. I have been unable to download the latest version of Skype for many months now.. I have googled and followed every post I can find on the subject and ended up with more rubbish in my hard drive that I cant get rid of and still no success.. With windows uninstalling was always a straight forward simple operation.. Ok forgive me I'm so frustrated.. I will try to explain the problem:

When the new version of skype arrived I tried to download it and after apparently downloading it says "Skype was unable to install the update because the old application cant be overwritten" so then I google and read that I need to uninstall the old version first.. why this happened I don't know as alwasy before new versions downloaded without a problem.. so when I find it (Skype.app) in finder it will not drag to trash.. though it does not seem to be in 'Applications' or 'Utilities' it seems to be amongst some pictures?.. I have tried to move it to Applications but again it seems it will not be moved?.. I also have a Skype 'disc image' in my trash and when I try to empty trash it says "The operation can’t be completed because the item “Skype_5.8.0.945.dmg is in use". It says this even after I quit skype. I then read somewhere that the way to get rid of it was use 'app cleaner' so I downloaded that and it didnt work and now i seem to be stuck with that in my dock and yet i cant find it anywhere else and it doesn't seem to do anything? All this happened months ago when after hours of frustration I just gave up and decided to live with the old version of skype.. Then today I was trying to clean up a few things I dont want and ended up trying again.. this time i downloaded another thing called AppTrap which is now also stuck in my trash because it didnt work either and now I cant get rid of that either! By now you are probably thinking I am a halfwit! well I have never been great with all this stuff but when I had a windows PC I managed to uninstall things without a problem.. I have found some explanations of how to solve these kind of issues that sound like you have to be not only a computer genius but also have endless free time which I just dont have.. can anyone help me? Thanks in advance!