Problems with running/installing stuff.

Hi, I just barely finished building a new computer and just installed Windows Vista Ultimate 64-bit with SP1 with my OEM disc. However whenever I try to install any programs that I've downloaded, it never works. For example, when I am trying open an installer file that I've downloaded it keeps saying "*name of program" has stopped working. This happens with a lot of files like .exe and .msi. When I try to download a zip program like CoreTemp, I get "Error 0x80004005: Unspecified error" whenever I try to extract the file because of the .exe file inside. Also a few of the Windows updates keep failing to install. The Problem Reports and Solutions says I'm missing 2 chipset drivers but I am unable to install them because of my problem. My computer has a Core i7 920 CPU, Gigabyte EX58-UD4P motherboard, Western Digital Caviar Black 640 GB, and a MSI Geforce 9600GT video card.

Oh yeah, the ONLY way that I am able to install stuff like drivers, software, etc is from the optical drive through CDs or DVDs.

Have you tried running the programs as admin by right clicking on them and run as admin?

Yes I have, but it still does the same thing.