I have a 64 bit windows 7 laptop but am currently using 32 bit java. My client crashes usually about 15 seconds after joining the server I play on. Most of the time It crashes while opening my inventory/chest/furnace or something of that nature, but often it crashes while doing nothing. And after It crashes, it won't open at all unless I restart my computer. All settings are as low as they can go, and I have allocated the max amount of ram.