Re-try: Partitioned '08 iMac, Win7, Radeon X1600, help with upgrading driver?

Question

I've been trying to use information found on other threads to update my driver but have had no success; my software and cpu are somewhat older than what I've been reading about. So.... I'm going to try this again before taking the thing to the local fixit shop (I don't want to do that...) And hopefully if there's someone in the same jam out there a search will bring them to this thread.
Is there anyone out there that can give me a simple 'do this, do this, do this, and do this' for my particular setup? I've used DriverSweeper prior to attempting installs, and Mobility Modder to get around AMD's Catalyst installer problems re:bootcamp.
I just wanna play my stupid GAMES, wah!
Here's part of my latest dxdiag:
Time of this report: 4/16/2012, 15:57:44
        Machine name: IMAC
    Operating System: Windows 7 Ultimate 32-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.111025-1505)
            Language: English (Regional Setting: English)
System Manufacturer: Apple Computer, Inc.
        System Model: iMac5,1
                BIOS: Default System BIOS
           Processor: Intel(R) Core(TM)2 CPU         T7600  @ 2.33GHz (2 CPUs), ~2.3GHz
              Memory: 4096MB RAM
Available OS Memory: 3056MB RAM
           Page File: 744MB used, 5366MB available
         Windows Dir: C:\Windows
     DirectX Version: DirectX 11
DX Setup Parameters: Not found
    User DPI Setting: 96 DPI (100 percent)
  System DPI Setting: 96 DPI (100 percent)
     DWM DPI Scaling: Disabled
      DxDiag Version: 6.01.7601.17514 32bit Unicode
Here is the current display info, FOLLOWED by the info if I restore the original driver (8.561.0.0):
Display Devices
           Card name:
        Manufacturer:
           Chip type:
            DAC type:
          Device Key: Enum\
      Display Memory: n/a
    Dedicated Memory: n/a
       Shared Memory: n/a
        Current Mode: 800 x 600 (32 bit) (1Hz)
         Driver Name:
Driver File Version:  ()
      Driver Version:
         DDI Version: unknown
        Driver Model: unknown
   Driver Attributes: Final Retail
    Driver Date/Size: , 0 bytes
         WHQL Logo'd: n/a
     WHQL Date Stamp: n/a
   Device Identifier: {D7B70EE0-4340-11CF-B123-B03DAEC2CB35}
           Vendor ID: 0x0000
           Device ID: 0x0000
           SubSys ID: 0x00000000
         Revision ID: 0x0000
  Driver Strong Name: Unknown
      Rank Of Driver: Unknown
         Video Accel:
       Deinterlace Caps: n/a
        D3D9 Overlay: n/a
             DXVA-HD: n/a
        DDraw Status: Not Available
          D3D Status: Not Available
          AGP Status: Not Available
Here is the ORIGINAL display info:
Display Devices
           Card name: ATI Mobility Radeon X1600
        Manufacturer: ATI Technologies Inc.
           Chip type: ATI Radeon Graphics Processor (0x71C5)
            DAC type: Internal DAC(400MHz)
          Device Key: Enum\PCI\VEN_1002&DEV_71C5&SUBSYS_0080106B&REV_00
      Display Memory: 1398 MB
    Dedicated Memory: 126 MB
       Shared Memory: 1272 MB
        Current Mode: 1440 x 900 (32 bit) (60Hz)
        Monitor Name: Generic PnP Monitor
       Monitor Model: Color LCD
          Monitor Id: APP9C59
         Native Mode: 1680 x 1050(p) (59.883Hz)
         Output Type: Internal
         Driver Name: atiumdag.dll,atiumdva.cap,atitmmxx.dll
Driver File Version: 7.14.0010.0630 (English)
      Driver Version: 8.561.0.0
         DDI Version: 9Ex
        Driver Model: WDDM 1.0
   Driver Attributes: Final Retail
    Driver Date/Size: 12/1/2008 20:29:34, 4033536 bytes
         WHQL Logo'd: Yes
     WHQL Date Stamp:
   Device Identifier: {D7B71EE2-3285-11CF-AD71-8A20A1C2CA35}
           Vendor ID: 0x1002
           Device ID: 0x71C5
           SubSys ID: 0x0080106B
         Revision ID: 0x0000
  Driver Strong Name: oem39.inf:ATI.Mfg:ati2mtag_M56:8.561.0.0:pci\ven_1002&dev_71c5
      Rank Of Driver: 00F62001
         Video Accel: ModeMPEG2_A ModeMPEG2_C
    Deinterlace Caps: {6E8329FF-B642-418B-BCF0-BCB6591E255F}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
                      {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
                      {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(YUY2,YUY2) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY
                      {6E8329FF-B642-418B-BCF0-BCB6591E255F}: Format(In/Out)=(UYVY,UYVY) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
                      {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(UYVY,UYVY) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
                      {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(UYVY,UYVY) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY
                      {3C5323C1-6FB7-44F5-9081-056BF2EE449D}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,2) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
                      {552C0DAD-CCBC-420B-83C8-74943CF9F1A6}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,2) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
                      {6E8329FF-B642-418B-BCF0-BCB6591E255F}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,1) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_PixelAdaptive
                      {335AA36E-7884-43A4-9C91-7F87FAF3E37E}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY DeinterlaceTech_BOBVerticalStretch
                      {5A54A0C9-C7EC-4BD9-8EDE-F3C75DC4393B}: Format(In/Out)=(NV12,0x3231564e) Frames(Prev/Fwd/Back)=(0,0,0) Caps=VideoProcess_YUV2RGB VideoProcess_StretchX VideoProcess_StretchY
        D3D9 Overlay: Not Supported
             DXVA-HD: Not Supported
        DDraw Status: Enabled
          D3D Status: Enabled
          AGP Status: Enabled
I love my Mac. But I love my Windows-only games.

Answer 1

The first part of your mcelog (the bit about " failed to prefill DIMM database from DMI data") strongly suggest one of the new RAM chips is defective. Start by simply putting the old one back in place and seeing if that helps. If it does, exchange the new faulty one with the seller for one that works. However, since you say yourself you aren't very tech savvy, it may be the case that you've simply purchased a RAM chip that is not compatible with your motherboard (although if both of the new chips are identical and the first one works, that may not be so).
When deciding to upgrade all the most vital hardware components of a machine, it's best to do it one piece at a time, and reconfigure the operating system to account for the new hardware. Uninstall old drivers, install new ones, change any personal settings related to the old hardware, reboot, make sure everything's fine and then repeat the process for every other new piece of hardware. Replacing everything at once without ensuring it will all work together increases the chances problems like this immensely---the problem itself may be very simple, but you've undertaken so many changes in such a short time that finding out what the problem is in the first place can be very complicated.