If you find IntellJ just hangs and you have the kill the process, then you restart and it hangs again, its probably an issue with your JDK. I followed the steps here marked workaround:
Basically this involved editing the JVM startup properties to disable cardmarking or some such. The details are all contained in the link.
IntelliJ worked perfectly afterward. Its quite ironic as I was thinking how much I liked IntelliJ just before it happened. At least it was an easy fix. I am using the version 10 Community edition.