well tell us some of your components and your power supply and we could probably give you an idea whether or not you are overloading your psu, also get a motherboard monitor for your system and check the voltages, if you are overloading the voltages will be on the low side from lack of power or on the really high side due to regulator malfunction from overloading.
Here's my pc specs and stuff
dell dimension 8200
2ghz P4, 1gb rdram (the expensive type ram)
73gb 10k raptor hdd, sata host controller card
external maxtor backup hdd, usb
3 19" monitors
PSU 250w (factory original)
bfg nvidia 6200 OC, agp 256mb ddr (requires minimum 250w)
with 2 monitors connected, one dvi and one vga
nvidia geforce mx 4000, pci 128mb ddr
with 1 monitor just for my business emails, nothing special
Here's what happens, when viewing video on either of the 2 monitors connected to the 6200 card then the dvi connected main monitor randomly blinks. Only the main monitor blinks which is strange. When the same video is moved to the monitor on the mx4000 card then the blinking stops.
So wonder what the deal is?
(edit) oh also, I only have 1 dvi port to connect to and the main monitor is the best one I have so there's not many options as far as rearranging my setup other than buying new stuff.