ATI Radeon Series X1600 AGP Adapter Problem?

Running Vista Ultimate and just yesterday the machine went into a deep coma
and I could not wake it by using the mouse or the space key. In fact I know
I set a screensaver but I hadn't seen it for awhile. I had to hard power the
computer back on to resume work. Thought it might have been the graphics
card so updated the drivers but the problem still persists. I now cannot
allow the computer to remain idle otherwise I get a screen with vertical pin
stripe lines running from top to bottom or a blank backlit screen. Could
this be a failing card or a buggy BIOS?
Just had a terrible thought --- Bad monitor?

ASUS P4P800-E mobo
Pentium 4 3.20GB
3071 MB RAM
435.09 Gigabytes Usable Hard Drive Capacity
239.81 Gigabytes Hard Drive Free Space

NEC DVD_RW ND-3540A ATA Device [CD-ROM drive]
LITE-ON COMBO SOHC-5232K ATA Device [CD-ROM drive]
MagicISO Virtual DVD-ROM0000 [CD-ROM drive]
SN5518B UJD401S SCSI CdRom Device [CD-ROM drive]
3.5" format removeable media [Floppy drive]

IOMEGA ZIP 250 USB Device [Hard drive] (246 MB) -- drive 4
Maxtor 6Y200P0 ATA Device [Hard drive] (203.92 GB) -- drive 0
Maxtor 91303D6 ATA Device [Hard drive] (13.03 GB) -- drive 1
QPS 0 IEEE 1394 SBP2 Device [Hard drive] (61.49 GB) -- drive 3
ST3160023AS ATA Device [Hard drive] (160.00 GB) -- drive 2

Radeon X1600/1650 Series Secondary [Display adapter]
Radeon X1600/X1650 Series [Display adapter]
DELL 2007WFP [Monitor] (20.0"vis, s/n HF7306746HUL, July 2006)

Board: ASUSTeK Computer Inc. P4P800-E Rev 1.xx
Bus Clock: 200 megahertz
BIOS: American Megatrends Inc. 1009.003 09/05/2005