many recent games will not run a 1.8 ghz cpu, what game or game types are you looking to play on?
You might be able to play Source engine type games (Left4Dead2, Counter Strike, Team Fortress 2[free2play now]
You most likely will not be able to play StarCraft 2, Metro2033.
Also, what's your video card?
be careful when you say that it will not play games because of a low clock speed. keep in mind that a 2.5 ghz 2920xm mobile cpu is on par with a 980x in gaming performance. clock speed is not what is important in this case, the problem is the architecture of a core 2 duo is just much to slow clock to clock compared to newer cpus.