Got a Lenovo computer that came with Win 7 Home Premium 32 bit. I upgrade the memory to 8gb and now want to install the 64 bit version. I download the 64 bit iso and extracted it to a dvd. At startup, it can't find the bootable files or something and ends up booting off the hard drive. Also when I try running the setup off the dvd, i get the message "This installation disc isn't compatible with your version of Windows". Any suggestions?