Upgrading to Photoshop CS

@acura90: since the copy of Photoshop 7 came with the machine, the first step is to confirm what kind of license you actually have and to find the serial number and any proof of purchase. @katarey correctly pointed to Adobe for official rules, and @Member#114696s observation about upgrading to a later CS release is relevant because which versions you can upgrade to depends on the qualifying product. The practical checklist below covers what most people run into when moving from PS7 to a CS-era product.

• Verify license type (retail, OEM, educational, volume) and keep the serial/proof of ownership handy; upgrade offers require a qualifying previous license.
• Back up all user assets: presets, brushes, actions, custom shapes, patterns and the Plugins folder. Export or copy these before you touch the installer.
• Check the target Photoshop system requirements against the machine you have; older PCs may run newer CS releases very slowly.
• Inventory third-party plugins and find updated versions; many plugins written for PS7 either need updates or will not run in later CS builds.
• When ready, follow the official upgrade purchase/activation path, install the upgrade, apply updates/patches, then restore presets and reinstall compatible plugins.

Cautions: OEM or bundled licenses can restrict transfer, and plugin/script compatibility can be the biggest headache. If reading this years later, note that Adobe later shifted to a subscription model, so upgrade routes that existed in 2007 may no longer be available.