Please suggest if the below laptop configuration will hold good for gaming for at least two years or so?
1. 4th Generation Intel® Core™ i7-4500U processor (4M Cache, up to 3.0 GHz)
2. 8GB 2 DIMM (2x4GB) DDR3L 1600Mhz
3. 1TB 5400RPM SATA Hard Drive
4. AMD Radeon(TM) HD 8850M 2GB GDDR5
5. Windows 8, 64 bit
Will it be able to play next generation games like Watchdogs, etc.?
Not with a CPU that's designated with a U - those are made for ultra low power requirements and won't perform as well as their regular laptop counterparts, which in turn don't run as well as their desktop counterparts.
graphics will play current gen games at low to medium settings, with others being up to high settings for some lighter games.
the I7 4500u performs 10% worse (or less depending on who you check) compared to the I5 4200M, so it can still handle the majority of games at low and medium settings.
you're looking at the Inspiron 15 3537?