Dual monitor problem using DELL 2405 FPW

Just posted this at DELL XPS video forum but thought I'd post here too in case anybody can assist:" I just set up my new DELL 2405 FP and it works 100% great in DVI mode in 1920x1200x32 on my XPS Gen 4 with a Radeon X850 XT PE card (hooray!). I would like to run this big monitor with a smaller DELL, an 1801 FP, at the same time. I've done this successfully with the 1801 and until two weeks ago with a DELL 2005 FP. However, when I now connect my smaller DELL LCD 1801 FP to the same ATI video card using the blue video cable (for analog?), that LCD annunciates on booting up Windows XP "Input signal out of Range....Power Management Mode in 18 secs." And 18 secs later, the smaller LCD falls asleep and no image appears. Meantime, the 2405 is humming along just great. Why is this? Is the Radeon card not powerful enough to drive both monitors at the same time? I have a 3.80Ghz processor, 1024 RDRAM, and a 460W PSU. Every USB port on the PC is taken up with peripherals for Flight Simulator 2004 so I am running a huge amount of hardware off the Gen 4 but it seems to handle it all without a hiccup. I have the latest DELL video drivers for my ATI 850 video card dated March 2006, just installed them tonight. I appreciate any guidance or assistance here, thanks. JS"Thanks to any AVSIMmers in advance for any assistance with this.JS