When I choose "Exit" from the Steam menu, Steam will exit like it should, but will then start again. If I choose Exit a second time it will stay exited.

Processor Information:
    Vendor:  AuthenticAMD
    Speed: 2211 Mhz
    2 logical processors
    2 physical processors
    HyperThreading:  Unsupported
    FCMOV:  Supported
    SSE2:  Supported
    SSE3:  Supported
    SSSE3:  Supported
    SSE4a:  Unsupported
    SSE41:  Unsupported
    SSE42:  Unsupported

Network Information:
    Network Speed:  

Operating System Version:
    Ubuntu 12.10 (64 bit)
    Kernel Name:  Linux
    Kernel Version:  3.5.0-21-generic
    X Server vendor:  The X.Org Foundation
    X Server release:  11300902

Video Card:
    Driver:  NVIDIA Corporation GeForce 7800 GT/PCIe/SSE2
    Driver Version:  2.1.2 NVIDIA 304.51
    Desktop Color Depth: 24 bits per pixel
    Monitor Refresh Rate: 60 Hz
    VendorID:  0x10de
    DeviceID:  0x92
    Number of Monitors:  1
    Number of Logical Video Cards:  1
    Primary Display Resolution:  1280 x 1024
Desktop Resolution: 1280 x 1024
    Primary Display Size: 14.80" x 11.85"  (18.94" diag)
                                            37.6cm x 30.1cm  (48.1cm diag)
    Primary Bus: PCI Express 16x
    Primary VRAM Not Detected
    Supported MSAA Modes:  2x 4x 8x 16x 

Sound card:
    Audio device: Realtek ALC850 rev 0

Memory:
    RAM:  3955 Mb

Miscellaneous:
    UI Language:  English
    LANG:  en_AU.UTF-8
    Microphone:  Not set
    Total Hard Disk Space Available:  255215 Mb
    Largest Free Hard Disk Block:  137396 Mb

Installed software:

Recent Failure Reports: