Feisty Beta on x86_64 freezed after login

Were you by any chance using Firefox (even out of focus)?

hmm, well it may be that it isnt generating logs, as it cuts out too quickly and violently, not even giving logs the chance to be created.

Cesare,
I'm not sure for 100%, but seems you're right about the filrefox.
I will test this case today.

The problem is not related to Firefox.
Already tryed to remove
   compiz and desktop effects,
   nspluginwrapper for FF,
   firefox
   change X driver to fglrx and back.
   install all updates.

Unfortunately, the system is stop responce after 5-15 min within GUI desktop, even if
it's completley idle.

Any ideas how to debug this problem ??

Can you switch to the console - CTRL+ALT+F1, login, and then run

sudo /etc/init.d/gdm stop

To completely shutdown the graphical environment, leave it an hour and see if it still crashes. This may allow us to focus on the graphical area for problem diagnosis.

Ok, It's not related to graphical area. In the console mode it was stucked after 5-6 min.
1. I have run "top", leave it working and system freezed again.
      Over tite row of "top" followed message appeared:
      [ 421.293737] BUG: soft lockup detected on CPU#0!
2. In single user mode, on console it WASN'T hapened.

  I have prepared lsof and ps -ef output before system halted in conlole.
   If it's interested I can send it too.

Thanks.

s/lsof/lsmod/

please attach the ouput of command lspci

00:00.0 Host bridge: nVidia Corporation nForce3 250Gb Host Bridge (rev a1)
00:01.0 ISA bridge: nVidia Corporation nForce3 250Gb LPC Bridge (rev a2)
00:01.1 SMBus: nVidia Corporation nForce 250Gb PCI System Management (rev a1)
00:02.0 USB Controller: nVidia Corporation CK8S USB Controller (rev a1)
00:02.1 USB Controller: nVidia Corporation CK8S USB Controller (rev a1)
00:02.2 USB Controller: nVidia Corporation nForce3 EHCI USB 2.0 Controller (rev a2)
00:05.0 Bridge: nVidia Corporation CK8S Ethernet Controller (rev a2)
00:06.0 Multimedia audio controller: nVidia Corporation nForce3 250Gb AC'97 Audio Controller (rev a1)
00:08.0 IDE interface: nVidia Corporation CK8S Parallel ATA Controller (v2.5) (rev a2)
00:09.0 IDE interface: nVidia Corporation CK8S Serial ATA Controller (v2.5) (rev a2)
00:0a.0 IDE interface: nVidia Corporation CK8S Serial ATA Controller (v2.5) (rev a2)
00:0b.0 PCI bridge: nVidia Corporation nForce3 250Gb AGP Host to PCI Bridge (rev a2)
00:0e.0 PCI bridge: nVidia Corporation nForce3 250Gb PCI-to-PCI Bridge (rev a2)
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
01:00.0 VGA compatible controller: ATI Technologies Inc RV350 AS [Radeon 9550]
01:00.1 Display controller: ATI Technologies Inc RV350 AS [Radeon 9550] (Secondary)
02:08.0 Network controller: RaLink Ralink RT2600 802.11 MIMO
02:0c.0 FireWire (IEEE 1394): VIA Technologies, Inc. IEEE 1394 Host Controller (rev 46)

Seems your network card causes the lookup. See the bug I linked