Legally, only if the license permits it. Most commercial games (Steam, Epic, Battle.net, EA App, GOG, disc-based) are licensed **per user/account**, not per household or device. Installing on a second PC without a second license is copyright infringement.
| Method | How It Works | Simultaneous Play? |
|---|---|---|
| Steam Family Sharing | Authorize PC #2 → Friend/Family logs in with *their* Steam account → Accesses your library. | Yes (different accounts) |
| Steam Remote Play Together | Host on PC #1 → Invite friend (no game ownership needed) → Streams video/input. | Yes (local co-op/MP only) |
| Cloud Gaming (GeForce NOW, Xbox Cloud, Boosteroid) | Stream your owned games from cloud server to any PC/Mac/Phone/TV. | Yes (your account on cloud) |
| Buy Second Copy | Purchase another license (often cheap on sales / key resellers like Fanatical, GreenManGaming). | Yes (two accounts) |
| Local LAN / Parsec / Sunshine | Stream from your main PC to a laptop/HTPC on same network or via internet. | Yes (your account) |
Bottom Line: Install on your own desktop + laptop? Fine (sequential play). Give installer to friend? Not fine. Use Family Sharing or Cloud Gaming for simultaneous access.