Can you be more specific in what is taking ages to load?
You can run a basic apple hardware test on your mac (boot mac holding D) this would verify the major hardware components are fine, in my opinion it sounds either software based or hard drive related but i wouldn't confirm this without more information. If its taking ages to boot up and load the home screen; do you have lots of items on your desktop? Or do you have loads of startup items. (system preferences - accounts - your user - login items and delete everything in there then try a reboot.