Recently Upgraded to Windows 8, cannot connect to store

I am unable to connect to the itunes store. I get an error message "Itunes could not connect to the itunes store....." Ending with an 0x80090330. I AM obviously connected to the internet and have also checked to make sure itunes is allowed through my firewall etc. My passwords etc are correct as well (I have tried basic troubleshooting. I am computer literate.) Also, I cannot update quicktime using the apple software update app. It gives me an error message saying that it has an invalid signature and will not be installed. I even tried downgrading to itunes 9, but that did not work either. I have done some searching on the forums, which the error number led me to a program that had something to do with a time stamp in the registry or something like that, but could not get the program to run on my OS. Help here would be greatly appreciated. Thanks in advance.