I've installed new NB version, but it don't run. It show a message box with "Jvm creation failed" message.
It don't happen every run. Sometimes it runs and works without problems. But 3 times from 4 it shows error.
If I run netbeans.exe from console the output is:
"
The launcher has determined that the parent process has a console and will reuse
 it for its own console output.
Closing the console will result in termination of the running program.
Use '--console suppress' to suppress console output.
Use '--console new' to create a separate console window.
Error occurred during initialization of VM
Could not reserve enough space for object heap
"
My netbeans options:
netbeans_default_options="--locale en_US -J-client -J-Xss2m -J-Xms128m -J-Xmx512m -J-XX:PermSize=32m -J-XX:MaxPermSize=384m -J-Dapple.laf.useScreenMenuBar=true -J-Dapple.awt.graphics.UseQuartz=true -J-Dsun.java2d.noddraw=true "
I've changed Xmx to 256m and now it start without errors.
What's wrong with Xmx512m? There is 4Gb of RAM on my PC and it has a lot of free memory.
I had the same problem a couple months ago with NB7beta on another PC with windowsXP. The same error periodically.

NetBeans IDE 7.0 RC2 (Build 201104070802)
java version "1.6.0_24"
Java(TM) SE Runtime Environment (build 1.6.0_24-b07)
Java HotSpot(TM) Client VM (build 19.1-b02, mixed mode, sharing)