2GB DDR2 RAM

Hi Everyone, My laptop is hp c6720s core 2duo t5670 processor, window 10 installed. It's working fine with 2gb ddr2 ram in one slot. when i put another 2gb ram in another slot (total 4b gb in two slots), then it's start crashing on window home screen. Anykind of help or suggestion will be...

I have built an htpc with such configuration. I will mostly watch videos but sometimes wanna play old (pre 2012) games too. Will this gpu be bottlenecked by the cpu and ram while gaming? Screen resolution is 1366x768. ... I am using windows 7 starter edition by the way, stripped it down as much...