Prior to buying Vista Home Premium, I upgraded to new motherboard, new CPU (Intel Core 2 e6600), new video card, big power supply, 4GB ram...well, an entire new computer. I ran the pre-install advisor and removed a couple of programs as recommended.
First I tried the upgrade path from Windows XP Media Center Edition...wanting to keep my software and settings in place. The install started out OK...I saw a message on screen that said this could take several hours, so I went away...and came back the next morning. I had a blank screen and and no activity from the computer...just fan noise. I powered down and re-booted...same result. Again I reboot and choose windows install at the final screen...get the message that the install failed - and went back to XP.