•The command-line drive utility fsck is invoked by booting into single-user mode (command+s at startup) and then typing fsck -yf
•I don't know why Limewire is crashing for you. It may be the Java update, since you mention the problem started occurring after a software update. In any case, if you're using the official Limewire client, realize that most people strongly prefer other Limewire clients such as Acquisition.