Can't no such thing. By year 3 in every PC your feeling the performance of the video card is lacking and require a upgrade, by year 5 the computer is no longer compatible with current software / hardware demands (want USB3 speed on that XP system, can't happen unless you replace the computer entirely). All HARDWARE Warranties spell out no more then 3 year on parts, so in year 4 or 5 your risking using the computer (out of warranty) and if something breaks, your on your own.
If your looking for furture proof gaming, get a NexGen Console. PS3/Xbox lasted 10 years AND STILL GOING *_* ! That is two full PC replacements!