Java HotSpot Virtual Machine

Ok, so I am in a bit of trouble...
Let me tell you what happened.

I was designing a method for an assignment, using Dr. Java. It was a very bad method, full of bugs. Extremely awkward. I think it involved an infinite loop putting hash maps into a big hash map. Inevitably, it ran very slowly and slowed down until eventually a window popped up announcing that there was no memory left, and asked if I would like to increase the memory. I agreed and set the memory as high as it would go (dumb move, I only have 2G of memory anyway, and I think I set it to 4G). The window said that the changes would come into effect once I restarted Dr. Java, so I dutifully closed the program and went to start it up again, when lo and behold, an error message!

Java Virtual Machine Launcher: Could not create the Java virtual machine.

So I can no longer open Dr. Java. I have since re-installed my JRE, JDK, and Dr. Java, but I still have the same problem. (Actually it seems that Dr. Java doesn't get installed, it just goes...) Also, note that I can still run Java applets and apps. Other information: I am using Vista, and I have the latest Java.

Also, I really need to get Dr. Java working again, so I can do more assignments :S

Thanks