My Minecraft crashes every 15 minutes, saying "Minecraft has ran out of memory".

Hello, my IGN is ZayaGaming and I'm having a terrible problem that I need help desperately with. Apparently, out of now where, my Minecraft crashes every 15 minutes or so. It claims it has run out of memory. Now for more information, I use a laptop and have 4.00G of ram. In which I use this laptop mainly just for Minecraft, so I've dedicated 2.00G of ram into the game itself. I've deleted a lot of useless files and I'm still having this problem where it glitches out a LOT, lags out, fps drops then crashes with the same exact message. I really want to fix this or it's going to ruin my experience for Minecraft. Please help!

Screenshot of Crash: http://gyazo.com/75ac02a30bbedb85c49b20d6a81b5a21