i have been mining steadily for over a week now with two 5870s in one rig and a 5830 and two 5850s in another.  now, whenever i look at guiminer, it always says "connection problems" for at least one card where the m/hash is normally at.   what is wrong?

thanks for the help.  I believe my pc may be too hot, and either the GPUs or my power supply cannot handle the heat, since my room is probably over 80 degrees F.  soon, I plan to better cool the computer. 
thanks again

I ran a test on my pc.  The 5830 and the sapphire 5850 ran stable without the asus 5850.  however, when i started the asus 5850 the M/hash began to fluctuate.  So it seems my psu can't handle all my cards.  however, I was able to run it for a week and my psu handled it fine.  When i overclocked the asus 5850, could there be any settings left over that allowed it to draw more power?
thanks

I have recently setup a new mining rig.  here are the specs below:
msi 750i motherboard
core 2 duo e6600
4gb ddr2
xfx 5830 (235M/hash)
sapphire 5850(275M/hash)
asus directcu 5850(275M/hash)
windows xp OS
750w psu
I have been mining on the computer for close to a week now, and always get the same M/hash with minimal fluctuations.  I have msi afterburner installed, and I would always have 100%gpu usage on all of my cards.  Today, I tried to overclock my asus 5850.  I increased the clock to 775mhz, but the m/hash on my other cards started to fluctuate, so i reset it to stock.  However, my 5830 and sapphire 5850 now has large m/hash fluctuations.  The 5850 varies from 180-240 M/hash and the sapphire 5850 varies from 200-275 M/hash,  but the asus 5850 is unaffected.  also, whenever I enter msi afterburner, my asus 5850 is always at 100% usage, but the 5830 and sapphire 5850 usage fluctuates between 80-97% usage. 
What could be causing the problem?

I have reinstalled windows xp with a low level format, loaded all drivers, installed complete CCC drivers, but i still get the error message!  I have done everything I can think of, but i still can't get the program to run.  everytime, i get the same error message reading "the application configuration is incorrect."  Is there anything else i need to install to get Guiminer to work?

i have tried to run CCC, but whenever i install it, it automatically disables the second video card.  I have searched extensively, and cannot find a way to enable the second card. 
still,  shouldn't the GUIminer program start, even without any drivers, and list my cpu as a device?

I am running just the display driver, which says it has opencl support.  However, i can't even get GUIminer to even open.  i am running guiminer 2011 05 01.

I have installed all necessary drivers on windows xp pro.  I downloaded guiminer and ran the program, but every time i try to run it, i receive an error message saying"the application has failed to start because the application configuration is incorrect.  reinstalling the application may fix this problem".  I have reloaded windows twice and have reinstalled guiminer several times. 
any advice on how to fix the problem?

i have tried making a dummy plug and switching the inputs between the cards.  neither of these things worked.  GPU-Z and MSI afterburner both detect 2 cards, but Catalyst control center only detects 1.
  is there anything else i could try?
EDIT:  CCC detects the second display adapter, but lists it as "Disabled".  is there a way to enable it?

dummy plug?
EDIT:  looked it up.  do i need this to run a second GPU?

I am trying to run a 5830 and a 5850 on a single computer.  after installing the latest drivers, GUIminer only recognizes 1 card named "Cypress".  i have tried different drivers, but i cannot get guiminer to work on both of my cards. 
any advice please?

sucessfully traded 18btc for usd.  went smooth.  will trade with again.