I remember desperately trying to upgrade my franken-PC, the guts of a Dell prebuilt that I'd moved over to a fresh case, with a Pentium 4. Some shiny new RAM and a bigger hard disk, all in the hope of running this strange game called Oblivion that I'd read about in a magazine.
Eventually, I've managed to get into it, and muddle my way through this dank and weird dungeon, with a bunch of dialogue that made little sense... and was then rewarded with the most amazing sight, as I popped my head out of the last door and saw that bright blue sky over the island, and the beautiful river dancing ahead of me.
I still haven't beaten that for a moment of jaw-dropping joy!