Did you install over the net or save the installer to your HDD. The latter I would recommend. Installing over the net can result in temporary pauses & loss of ...efficiency in installation & downld. This might sound crazy but I had an installation issue & I solved it by rebooting after downlding the installer. Then installing. But someone else tried that & it didn't make any difference for them. And I know it's a pain rebooting. But rebooting can clear the OS & ram of previous activities. If the installation is the only process happening then there's a much better chance of success if there is any difficulty.

The last resort is to clean up your registry. If you don't have a decent registry cleaner there's some HERE (click on link) (Some of those are free I think from memory.)

If you still have problems then there is an alternative installer I think. You just unzip it & use it. See Here about 'other' version.