Merci pour ta réponse
J'ai enlevé la barrette mémoire et le problème est toujours présent.
Voila ce que la console affiche après 2 plantage à la suite qui viennent de se produire :
09/07/08 19:28:34 com.apple.launchctl.System[2] launchctl: Please convert the following to launchd: /etc/mach_init.d/dashboardadvisoryd.plist
09/07/08 19:28:34 com.apple.launchctl.System[2] launchctl: Please convert the following to launchd: /etc/mach_init.d/IIDCAssistant.plist
09/07/08 19:28:34 com.apple.launchd[1] (com.apple.IIDCAssistant) Conflict with job: 0x100920.IIDCAssistant over Mach service: com.apple.IIDCAssistant
09/07/08 19:28:34 com.apple.launchd[1] (org.apache.httpd) Unknown key: SHAuthorizationRight
09/07/08 19:28:34 com.apple.launchd[1] (org.cups.cups-lpd) Unknown key: SHAuthorizationRight
09/07/08 19:28:34 com.apple.launchd[1] (org.cups.cupsd) Unknown key: SHAuthorizationRight
09/07/08 19:28:34 com.apple.launchd[1] (org.ntp.ntpd) Unknown key: SHAuthorizationRight
09/07/08 19:28:38 com.apple.launchd[1] (com.apple.ftpd) Unknown key: SHAuthorizationRight
09/07/08 19:28:38 com.apple.launchd[1] (com.openssh.sshd) Unknown key: SHAuthorizationRight
09/07/08 19:28:42 org.apache.httpd[28] httpd: Could not reliably determine the server's fully qualified domain name, using imac-de-bruno-moyon.local for ServerName
09/07/08 19:28:50 com.apple.SystemStarter[32] Starting XIMETA LPX Protocol
09/07/08 19:28:50 com.apple.SystemStarter[32] kextload: extension /System/Library/Extensions/netlpx.kext appears to be loadable
09/07/08 19:28:50 com.apple.SystemStarter[32] kextload: loading extension /System/Library/Extensions/netlpx.kext
09/07/08 19:28:50 com.apple.SystemStarter[32] kextload: sending 1 personality to the kernel
09/07/08 19:28:50 com.apple.SystemStarter[32] kextload: extension /System/Library/Extensions/netlpx.kext is already loaded
09/07/08 19:28:50 com.apple.SystemStarter[32] Starting XIMETA NDAS Service
09/07/08 19:28:50 com.apple.SystemStarter[32] Started.
09/07/08 19:30:51 com.apple.launchd[1] (com.apple.UserEventAgent-LoginWindow[72]) Exited: Terminated
09/07/08 19:30:51 com.apple.launchd[98] (com.apple.FolderActions.folders) Path monitoring failed on "/Volumes/CINEBOX-320": No such file or directory
09/07/08 19:30:52 com.apple.launchd[98] (com.apple.FolderActions.folders) Path monitoring failed on "/Volumes/CINEBOX-320": No such file or directory
09/07/08 19:30:54 Dock[108] _DESCRegisterDockExtraClient failed 268435459
09/07/08 19:31:08 MagicMenuHotKeyDaemon[135] Started
09/07/08 19:31:08 [0x0-0x15015].com.stuffit.MagicMenu[131] 2008-07-09 19:31:08.986 MagicMenuHotKeyDaemon[135:10b] Started
09/07/08 19:31:10 quicklookd[119] [QL ERROR] 'Creating thumbnail' timed out for '<QLThumbnailRequest /Users/nono/Desktop/juste une fois-.avi>'
09/07/08 19:31:10 TheTube Helper[133] LCC Scroll Enhancer loaded
09/07/08 19:31:20 quicklookd[136] [QL ERROR] 'Creating thumbnail' timed out for '<QLThumbnailRequest /Users/nono/Desktop/Voleurs De Chevaux.avi>'
09/07/08 19:31:21 com.apple.quicklook[141] Wed Jul 9 19:31:21 imac-de-bruno-moyon.local quicklookd[141] <Error>: CGContextClosePath: no current point.
09/07/08 19:31:21 com.apple.quicklook[141] Wed Jul 9 19:31:21 imac-de-bruno-moyon.local quicklookd[141] <Error>: CGContextClosePath: no current point.
09/07/08 19:31:21 com.apple.quicklook[141] Wed Jul 9 19:31:21 imac-de-bruno-moyon.local quicklookd[141] <Error>: CGContextClosePath: no current point.
09/07/08 19:31:21 com.apple.quicklook[141] Wed Jul 9 19:31:21 imac-de-bruno-moyon.local quicklookd[141] <Error>: CGContextClosePath: no current point.
09/07/08 19:31:28 [0x0-0x1a01a].com.apple.systemevents[138] com.apple.FolderActions.enabled: Already loaded
09/07/08 19:31:31 quicklookd[141] [QL ERROR] 'Creating thumbnail' timed out for '<QLThumbnailRequest /Users/nono/Desktop/The Bank Job.avi>'
09/07/08 19:33:47 com.apple.launchctl.System[2] fsck_hfs: Volume is journaled. No checking performed.
09/07/08 19:33:47 com.apple.launchctl.System[2] fsck_hfs: Use the -f option to force checking.
09/07/08 19:33:50 com.apple.launchctl.System[2] launchctl: Please convert the following to launchd: /etc/mach_init.d/dashboardadvisoryd.plist
09/07/08 19:33:50 com.apple.launchctl.System[2] launchctl: Please convert the following to launchd: /etc/mach_init.d/IIDCAssistant.plist
09/07/08 19:33:50 com.apple.launchd[1] (com.apple.IIDCAssistant) Conflict with job: 0x100ad0.IIDCAssistant over Mach service: com.apple.IIDCAssistant
09/07/08 19:33:50 com.apple.launchd[1] (org.apache.httpd) Unknown key: SHAuthorizationRight
09/07/08 19:33:50 com.apple.launchd[1] (org.cups.cups-lpd) Unknown key: SHAuthorizationRight
09/07/08 19:33:50 com.apple.launchd[1] (org.cups.cupsd) Unknown key: SHAuthorizationRight
09/07/08 19:33:50 com.apple.launchd[1] (org.ntp.ntpd) Unknown key: SHAuthorizationRight
09/07/08 19:33:55 com.apple.launchd[1] (com.apple.ftpd) Unknown key: SHAuthorizationRight
09/07/08 19:33:55 com.apple.launchd[1] (com.openssh.sshd) Unknown key: SHAuthorizationRight
09/07/08 19:33:59 org.apache.httpd[28] httpd: Could not reliably determine the server's fully qualified domain name, using imac-de-bruno-moyon.local for ServerName
09/07/08 19:33:59 com.apple.launchd[1] (org.apache.httpd) Throttling respawn: Will start in 9 seconds
09/07/08 19:34:01 com.apple.launchd[1] (org.apache.httpd) Throttling respawn: Will start in 7 seconds
09/07/08 19:34:07 com.apple.SystemStarter[32] Starting XIMETA LPX Protocol
09/07/08 19:34:07 com.apple.SystemStarter[32] kextload: extension /System/Library/Extensions/netlpx.kext appears to be loadable
09/07/08 19:34:07 com.apple.SystemStarter[32] kextload: loading extension /System/Library/Extensions/netlpx.kext
09/07/08 19:34:07 com.apple.SystemStarter[32] kextload: sending 1 personality to the kernel
09/07/08 19:34:07 com.apple.SystemStarter[32] kextload: extension /System/Library/Extensions/netlpx.kext is already loaded
09/07/08 19:34:07 com.apple.SystemStarter[32] Starting XIMETA NDAS Service
09/07/08 19:34:07 com.apple.SystemStarter[32] Started.
09/07/08 19:34:09 com.apple.launchd[1] (com.apple.UserEventAgent-LoginWindow[71]) Exited: Terminated
09/07/08 19:34:09 com.apple.launchd[90] (com.apple.FolderActions.folders) Path monitoring failed on "/Volumes/CINEBOX-320": No such file or directory
09/07/08 19:34:11 com.apple.launchd[90] (com.apple.FolderActions.folders) Path monitoring failed on "/Volumes/CINEBOX-320": No such file or directory
09/07/08 19:34:26 MagicMenuHotKeyDaemon[129] Started
09/07/08 19:34:26 TheTube Helper[125] LCC Scroll Enhancer loaded
09/07/08 19:34:26 [0x0-0x13013].com.stuffit.MagicMenu[123] 2008-07-09 19:34:26.310 MagicMenuHotKeyDaemon[129:10b] Started
09/07/08 19:34:27 quicklookd[112] [QL ERROR] 'Creating thumbnail' timed out for '<QLThumbnailRequest /Users/nono/Desktop/Voleurs De Chevaux.avi>'
09/07/08 19:34:28 com.apple.quicklook[133] Wed Jul 9 19:34:28 imac-de-bruno-moyon.local quicklookd[133] <Error>: CGContextClosePath: no current point.
09/07/08 19:34:28 com.apple.quicklook[133] Wed Jul 9 19:34:28 imac-de-bruno-moyon.local quicklookd[133] <Error>: CGContextClosePath: no current point.
09/07/08 19:34:28 com.apple.quicklook[133] Wed Jul 9 19:34:28 imac-de-bruno-moyon.local quicklookd[133] <Error>: CGContextClosePath: no current point.
09/07/08 19:34:28 com.apple.quicklook[133] Wed Jul 9 19:34:28 imac-de-bruno-moyon.local quicklookd[133] <Error>: CGContextClosePath: no current point.
09/07/08 19:34:39 quicklookd[133] [QL ERROR] 'Creating thumbnail' timed out for '<QLThumbnailRequest /Users/nono/Desktop/The Bank Job.avi>'
09/07/08 19:34:40 [0x0-0x17017].com.apple.systemevents[131] com.apple.FolderActions.enabled: Already loaded
09/07/08 19:34:47 com.apple.launchctl.System[2] BootCacheControl: could not fetch history: Cannot allocate memory
09/07/08 19:34:47 com.apple.launchctl.System[2] BootCacheControl: could not stop cache/fetch history: Cannot allocate memory
09/07/08 19:34:55 quicklookd[136] [QL ERROR] 'Creating thumbnail' timed out for '<QLThumbnailRequest /Users/nono/Desktop/lei-ud.avi>'
09/07/08 19:35:06 quicklookd[143] [QL ERROR] 'Creating thumbnail' timed out for '<QLThumbnailRequest /Users/nono/Desktop/juste une fois-.avi>'