Msi fx 5700 ultra 5900xt compatibility

Question

Hi
I recently bought a MSI fx5700 ultra to replace my ge force 4200 ti, However when I installed it is was a no go ran for about 10 seconds then the power switched of and the would not re start.  returned it to the shop who confirmed it was a dud then because no replacements are available loaned me a 5700 standard till they could get a new 5700 ultra.  ( the 5700 ran fine in my machine)  A few weeks went by then the shop contacted me informing me that could not get a 5700 ultra but would I be happy with a MSI 5900 xt which was satisfactory to me.  I installed the MSI 5900xt the machine started and windows xp loaded and detected the new hardware and all seamed fine until I went into a 3D game then strange things started to appear on the screen.  I re started the computer but even at the POST screen the screen was full of small vertical lines all over the screen and I could not get xp to load.  Back to the shop who again loaned me the 5700 standard which again worked fine.  and they confirmed the 5900xt was a faulty card.  
My system is:
P4 2.53 gig 533 front system bus
ASUS p4pe motherboard AGP 4 only 1.5 volt
1 gig ram
Sound blaster live
a good quality power supply (thermo ??? 480 watt)
2x120 gig hard drives
cd writer.
My question are
1/ As I understand it both cards are backward compatible with agp 4 / 1.5 volt. is this true or an I damaging the cards by installing them into my asus p4pe motherboard?
2/ Is it common to fine a faulty batch of cards? I have been building my own computers for about 6 years with no hardware problems until the 5700 ultra drama.
3/ Can any one suggest any thing else I may be doing wrong?
PS all my system is standard eg not over clocked etc.
Thanks in advance for any help anyone may be able to give
Bob

Answer 1

Thanks for the reply
the power supply is a Thermal Take silent pure power
Specifications:
Designed for AMD K7 and Intel ATX +12V 1.1 and ATX 2.03 version (Fully Support Pentium 4)
Serial ATA (Advanced Technology Attachment)
Active PFC (Power Factor Correction)
Peak Output: 550W
Two adjustable manual fan speed controls for use in the front and rear side of the case. (From 1300 RPM at 25°C~ 4800 RPM at 90°C).
Temperature Automatic Fan Speed Control
Noise: 17 dBA at 1300 RPM, 45 dB at 4800 RPM
Dual fans power supply
Xaser badge on side panel w/ black / silver color printing
Specifications:
Type: ATX
Maximum Power: 480W
PFC: Active
Power Good Signal: 100-500ms
Hold-up Time: >16ms at Full Load
Efficiency: >65%
Over Voltage Protection: +5V trip pointOverload Protection: Not specified
Input Voltage: 100 - 240 Vrms
Input Frequency Range: 47-63 Hz
Input Current: 8A
Output: +3.3V@30A;+5V@40A;[email protected];+12V@18A;[email protected];+5VSB@2A
MTBF: Not specified
Approvals: Not specified