Real sweepstakes have entrants. You filled out a form, mailed a card, scanned a code, clicked a box. If you have no memory of entering, it is because you did not enter. Memory is not the issue. The most polished version of this scam arrives on official-looking letterhead, names a famous sweepstakes brand, includes a fake check, and asks you to pay “taxes” or “processing fees” before the rest of the winnings are released. The check bounces a week later. The fees are gone.
Real prizes never require you to pay to receive them. Real lotteries do not notify winners by surprise letter or cold call. Foreign lotteries cannot legally be played from the US in the first place. If the message says you won something you did not enter, the only correct action is to throw it away.