|Fins free of dust? Did you visually check that the CPU fan is spinning at it's apparent normal speed at start up (that is a hot CPU normally, if the fan is not working properly, it can heat fast)?|
The 5.28V does sound a little high for normal, But I am not sure if it is enough out, but certainly very suspect. Someone will be along shortly who can confirm this I am sure (I have never had the need to take readings on these yet).
You have to be a little bit crazy to keep you from going insane.