My ubuntu 10.10 is freezing during downloading from my other computer on sftp. I thought it might be some nautilus issues so I tried it via command line and I got the same thing - after few minutes the whole computer freezes.

Mostly the numlock led is blinking (I've heard somewhere that this means a kernel panic), but not in 100% cases.

I dunno if that helps but here is a log from /var/log/message in the time that this happened. At least I hope so - it wasn't that big, when it happened before. But this looks quite "errorish", right? (isn't complete - see bottom)

Jan  5 17:57:49 tomas-ntb kernel: imklog 4.2.0, log source = /proc/kmsg started.
Jan  5 17:57:49 tomas-ntb rsyslogd: [origin software="rsyslogd" swVersion="4.2.0" x-pid="953" x-info="http://www.rsyslog.com"] (re)start
Jan  5 17:57:49 tomas-ntb rsyslogd: rsyslogd's groupid changed to 103
Jan  5 17:57:49 tomas-ntb rsyslogd: rsyslogd's userid changed to 101
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] Initializing cgroup subsys cpuset
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] Initializing cgroup subsys cpu
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] Linux version 2.6.35-24-generic (buildd@vernadsky) (gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5) ) #42-Ubuntu SMP Thu Dec 2 01:41:57 UTC 2010 (Ubuntu 2.6.35-24.42-generic 2.6.35.8)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] BIOS-provided physical RAM map:
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 0000000000000000 - 000000000009e800 (usable)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 000000000009e800 - 00000000000a0000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 0000000000100000 - 00000000dffa8000 (usable)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 00000000dffa8000 - 00000000dffb0000 (ACPI NVS)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 00000000dffb0000 - 00000000dffbff00 (ACPI data)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 00000000dffbff00 - 00000000dfff0000 (ACPI NVS)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 00000000dfff0000 - 00000000e0000000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 00000000ff700000 - 0000000100000000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 0000000100000000 - 0000000120000000 (usable)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  BIOS-e820: 0000000120000000 - 0000000140000000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] Notice: NX (Execute Disable) protection cannot be enabled: non-PAE kernel!
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] DMI 2.5 present.
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] AMI BIOS detected: BIOS may corrupt low RAM, working around it.
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] last_pfn = 0xdffa8 max_arch_pfn = 0x100000
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] Scanning 0 areas for low memory corruption
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000] modified physical RAM map:
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  modified: 0000000000000000 - 0000000000010000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  modified: 0000000000010000 - 000000000009e800 (usable)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  modified: 000000000009e800 - 00000000000a0000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  modified: 00000000000e0000 - 0000000000100000 (reserved)
Jan  5 17:57:49 tomas-ntb kernel: [    0.000000]  modified: 0000000000100000 - 00000000dffa8000 (usable)

... to long - for whole and better view click here