The word restaurant exists because of restore. In 1760s Paris, shops began selling bouillon restauratif — a rich, restorative broth intended to revive the exhausted. The place that served the broth inherited its name. A restaurant is, etymologically, a place that restores you.
Restore itself comes from Latin restaurāre, meaning 'to rebuild' or 'to renew'. The re- prefix means 'again', and the second element may relate to Proto-Indo-European *steh₂- ('to stand') — the image of erecting something that has fallen, standing it back up.
The word entered English via Old French in the 13th century and immediately found religious use. To restore a sinner was to return them to grace. To restore a king was to place them back on their throne. The Restoration of 1660 — Charles II returning to the English crown — gave the word its most famous historical use.
In modern English, restore spans the digital and physical. We restore old paintings, restore computer backups, restore buildings to their former glory. System Restore on a computer is the most literal application of the Latin meaning: to return something to a previous, working state.
The restorative — a drink or medicine that restores strength — preserves the oldest practical sense of the word.