I just had an experience where every time I would launch ColdFusion Builder beta 2, it would consume as much RAM as it could get. ColdFusion Builder seemed to launch properly but I couldn't interact with it: it was unresponsive as it went about its rampant RAM consumption and I had no choice but to kill the process.
I have Flash Builder 4 beta 2 installed as a plug-in and I was running it in Trial mode and accordingly every time I launched ColdFusion Builder, Flash Builder presented me with a registration screen. Normally, I'd have to clear this screen before ColdFusion Builder would launch completely but during the time when ColdFusion Builder was getting all whacked out on RAM, it was launching completely even while presenting this screen.
But the good news is that I got ColdFusion Builder working again by removing my "Adobe ColdFusion Builder workspace" directory; ColdFusion Builder then created a new one on its next launch and all was well. This is a drastic step that effectively completely resets ColdFusion Builder--but of course, that's a lot better than what I was dealing with. But actually, I was able to bail myself out on that and perhaps this will work for you too: rather than completely deleting my "Adobe ColdFusion Builder workspace" directory, I just renamed it (you could of course also move it) and then when the new one was created upon my next restart, I did a folder comparison of the 2 and I copied over a number of directories and files. By and large, what I copied over were those directories and files that were missing from the new directory, not those that were simply changed. In the end, as well as I could tell, when I next launched ColdFusion Builder, it not only launched properly but it was back in the state I wanted it in.