I've been having this terrible problem for a little while and just managed to get a picture of 'dead screen' for the first time and I am posting it to seek help.

Randomly, at irregular intervals (typically once a week), while working on something (it's been different things every time) my computer will just suddenly go dead - the screen turns to exactly the picture below (the lines flicker a little bit), it hangs there for a few seconds and then restarts.

Obviously this is extremely frustrating and I want to try to stop it.

I've searched numerous postings with similar keywords but nothing exactly the same as mine.

Does anyone have any idea what might be the cause of this?

I would post all my system settings and installed programs but the list is long and I don't know how much relevance each item would be. If you'd like to know something specific, please comment and I'll let you know whatever you need.

SPECS

C:\Users\Imray>systeminfo

    Host Name:                 Imray
    OS Name:                   Microsoft Windows 7 Professional
    OS Version:                6.1.7600 N/A Build 7600
    OS Manufacturer:           Microsoft Corporation
    OS Configuration:          Standalone Workstation
    OS Build Type:             Multiprocessor Free
    Registered Owner:          Imray - Owner
    Registered Organization:
    Product ID:                00371-152-9333854-85895
    Original Install Date:     06/09/1999, 5:45:21 PM
    System Boot Time:          22/03/2013, 8:58:18 AM
    System Manufacturer:       Gateway
    System Model:              DX4840
    System Type:               x64-based PC
    Processor(s):              1 Processor(s) Installed.
                               [01]: Intel64 Family 6 Model 37 Stepping 2 GenuineIntel ~3201 Mhz
    BIOS Version:              American Megatrends Inc. P01-A3        , 17/05/2010
    Windows Directory:         C:\Windows
    System Directory:          C:\Windows\system32
    Boot Device:               \Device\HarddiskVolume2
    System Locale:             en-us;English (United States)
    Input Locale:              en-us;English (United States)
    Time Zone:                 (UTC-05:00) Eastern Time (US & Canada)
    Total Physical Memory:     6,135 MB
    Available Physical Memory: 3,632 MB
    Virtual Memory: Max Size:  12,268 MB
    Virtual Memory: Available: 8,114 MB
    Virtual Memory: In Use:    4,154 MB
    Page File Location(s):     C:\pagefile.sys
    Domain:                    WORKGROUP
    Logon Server:              \\Imray-OWNER
    Hotfix(s):                 4 Hotfix(s) Installed.
                               [01]: KB971033
                               [02]: KB958559
                               [03]: KB977206
                               [04]: KB981889
    Network Card(s):           2 NIC(s) Installed.
                               [01]: 802.11n Wireless PCI Express Card LAN Adapter
                                     Connection Name: Wireless Network Connection
                                     DHCP Enabled:    Yes
                                     DHCP Server:     192.168.2.1
                                     IP address(es)
                                     [01]: 192.168.2.13
                                     [02]: fe80::1df1:5399:6890:91f6
                               [02]: Microsoft Virtual WiFi Miniport Adapter
                                     Connection Name: Wireless Network Connection 2
                                     DHCP Enabled:    Yes
                                     DHCP Server:     N/A
                                     IP address(es)

Graphics Card Specs

Name    ATI Radeon HD 5570
PNP Device ID   PCI\VEN_1002&DEV_68D9&SUBSYS_E142174B&REV_00\4&18A4B35E&0&0008
Adapter Type    ATI display adapter (0x68D9), ATI Technologies Inc. compatible
Adapter Description ATI Radeon HD 5570
Adapter RAM 1.00 GB (1,073,741,824 bytes)
Installed Drivers   atiu9p64 aticfx64 aticfx64 atiu9pag aticfx32 aticfx32 atiumd64 atidxx64 atidxx64 atiumdag atidxx32 atidxx32 atiumdva atiumd6a atitmm64
Driver Version  8.700.0.0
INF File    oem1.inf (ati2mtag_Evergreen section)
Color Planes    Not Available
Color Table Entries 4294967296
Resolution  1920 x 1080 x 59 hertz
Bits/Pixel  32
Memory Address  0xD0000000-0xDFFFFFFF
Memory Address  0xFBDE0000-0xFBDFFFFF
I/O Port    0x0000D000-0x0000DFFF
IRQ Channel IRQ 4294967293
I/O Port    0x000003B0-0x000003BB
I/O Port    0x000003C0-0x000003DF
Memory Address  0xA0000-0xBFFFF
Driver  c:\windows\system32\drivers\atikmpag.sys (8.14.1.6095, 181.00 KB (185,344 bytes), 06/09/1999 5:59 PM)