After I fixed the wiring to the vid card and upgraded my PSU, my PC was able to function properly again. My monitor still switched to "power saving" mode in stressful situations, mainly while gaming, and I concluded that it was overheating. Intel Active Monitor showed temperatures as high as 60C Processor Zone / 48C System Zone prior to the monitor going black.
I verified that voltages and fan speeds were fine, and the monitor never went into power saving unless the temp was at least 58C PZ / 46C SZ.
I then took my PC into a shop to get it cleaned with an air compressor and had the thermal paste redone. For two days after I got it out of the shop, it worked fine. It now sits at an idle temp of 31C PZ / 27C SZ, and so far has not exceeded 45C PZ / 32C SZ while gaming. Here is where the confusion begins for me.
My monitor is now black-screening and going into power saving even with the low temps. Two games, EVE Online and Fifa 10, black screen almost immedately. Counterstrike:Source is playable for a short time before switching to the black screen. In all cases, I can still hear audio of the game continuing without me while in power saving mode.
Any ideas would be much appreciated.
Microsoft Windows XP Home Edition
OS Service Pack Service Pack 2
DirectX 4.09.00.0904 (DirectX 9.0c)
Intel Pentium 4, 2666 MHz (20 x 133)
Orion XP400 420-watt PSU
Intel Rexburg D845GRG (3 PCI, 1 AGP, 2 DIMM, Audio, Video)
Chipset Intel Brookdale-G i845G
System Memory 1536 MB (PC3200 DDR SDRAM)
BIOS Type AMI (04/01/03)
Video Adapter ATI Radeon HD 3600 Series (512 MB)
Video Adapter ATI Radeon HD 3600 Series (512 MB)
IDE Controller Intel® 82801DB Ultra ATA Storage Controller - 24CB
SCSI/RAID Controller Silicon Image SiI 3512 SATARaid Controller
Disk Drive ST325031 8AS SCSI Disk Device (232 GB SATA)
Disk Drive SAMSUNG HD103SI USB Device (931 GB, USB)