Quicktime and itunes wont install. I have never had quicktime installed on my computer before

Question

I recently bought an ipod touch 4g and realized that I needed itunes to activate it. After downloading itunes it wouldn't install, no error messages or anything, when I click on the installer it just doesn't do anything.
After downloading several versions of itunes (older versions) I finally found one that started to install. Then it told me that I need Quicktime on my computer in order for it to install. So I downloaded the latest version of quicktime and had the same problem, when I click on the installer, nothing happens. I tried downloading older versions of quicktime but still had the same problem.
I have never had quicktime or itunes installed on this computer before, so I know that it isn't an older version of the program hidden in my computer that is preventing the installation from happening.
My computer is running on Windows 7. I know that there wasn't a problem with downloading the software, the files weren't corrupted or anything. There are no error messages, the software doesn't even partially install. When I click on the installer, nothing happens. I have tried running the programs as an administrator and that doesn't change anything.
I have tried so many different things, but can't remember everything that I tried. Yesterday I spent nearly 10 hours trying to sort this out because I was determined to get my ipod running. I only stopped when my internet credit ran out and today after buying some more, I am trying again. Please help.

Answer 1

I appreciate the quick response, thank you for that.
One thing I did try was windows cleanup utility and searched through the program files for all apple software, but had none. I even deleted the temp files on my computer, and on my internet browser, but nothing happened.
One thing that I didn't think of was deleting the installation files in my downloads folder, pretty silly of me but I didn't think it would make a difference. I also spent about 2-3gig on downloads yesterday and didn't want to delete the files but as a last resort I did and emptied my recycle bin, then downloaded a fresh copy of Quicktime and finally it installed!
Now I am in the process of downloading a fresh copy of iTunes, the download hasn't finished yet so I haven't had a chance to install it yet but I have a much better feeling about it this time after deleting all the old installation files from my downloads folder. If Quicktime worked after that, I am sure iTunes will.
I can't believe it was something so simple as deleting the installation files in my downloads folder and emptying the recycle bin. I had seriously gone through my entire computer looking for any little file that was related to Quicktime or iTunes. I didn't even think of the two most obvious places. I spent so much time and credit downloading multiple files and my computer even got a virus when trying to download a copy from an unauthorized source, I had no problem getting rid of the virus, but struggled with Quicktime and iTunes, that is why I got so frustrated! I feel like an idiot now :-P
Thank you for your help. I still havent installed iTunes yet, so fingers crossed. I think it will work now though.