"The Norton Utilities team has discovered a conflict with CrashGuard 3.5b1 and RAM Doubler. This issue is currently being resolved and an updated version of CrashGuard (3.5b2) should be available via Symantec's web site within the next few days.
If you experience problems with your machine crashing on restart after installing CrashGuard, please remove RAM Doubler and see if this is the issue."
Update: John Harrison just infomed me that "CrashGuard 3.5b2 is available on-line from Symantec's web site. Beta 2 resolves the issue with RAM Doubler crashing on startup with a Trap 9 exception."