The One In Barbados, part 2 - S9-E24
Corrected entry: The One in Barbados - the Anna Kournikova virus wiped out the whole computer's hard drive. Then when Ross finally gives his keynote speech, all his rather complex-looking presentation slides seem to be available again.
Correction: The slides we see consist of a couple of graphics of dinosaurs, one of fossils and one of DNA. These are surely commonplace amongst the audience for Ross' speech and he could have borrowed them from one or more of the many attendees.
tw_stuart