Sound Blaster X Fi Serial How Long Will This Gaming PC Last?

How long will this gaming PC last? - sound blaster x fi serial

How much time (like a good set of PC) with improvements such as additional graphics card and additional RAM required if?

Intel Core 2 Quad Extreme QX6850
PCI-Express Mainboard - SLI nForce 680i SLI (C55XE)
4 GB DDR2 667 MHz
768MB NVIDIA GeForce 8800 Ultra
1TB (2 x 500 GB) Serial ATA hard drive
Creative Labs Sound Blaster X-Fi Xtreme Gamer
Windows Vista Ultimate Edition
2 x Gigabit LAN
LightScribe Super Format 18x Dual Layer DVD Writer + R /-R / RW / RAM