What to do if ram is low and games run slow?

I have a 2g ram (1.75 usable)
4g (virtual ram)
2.5 ghz
Windows 7 x86 (32 bit)
Lenovo brand pc

Any game I play lags including miniclip games and I don't know why. The pc speed is fast but when I play a game it's another story
Any help with this is highly appreciated.

You replace the old RAM with larger RAM. See link.

Google razer game booster. It will close unneeded processes and thus free up so ram. Also Bazza had great advice as crucial.com is a very trusted company and will promise the RAM you buy from them will work on your machine. Also 2 GB RAM will not run games very well at all unless they are like before the 2,000's.