Can't Load Update For Itunes?

I have had itunes with an Wiondows XP 32 bit pc for many years. I now have a new pc with Window 7 64bit, i7-2600, 16 G RAM, and 1T of memory. My problem is I can not load itunes 10.6.3 into the pc. When I try, the program says it was interupted and the change did not take place. It then asks me to press finish or cancel. When I press finish, the program says thank you and gives me the4 option to store the program in G. I no longer have a G as that has been replaced by H. There is no opportunity to change the save location to H. and simply says to load the external disk, which does not exist.When I try to uninstal the itunes programs by strting with itunes first, the pc says that ituneshelper. Resources is not a valid short name.