RE: display turns into a screen of small shimmering colored patterns and the computer ceases to respond to any command.
Can you test this monitor on a different PC or a different monitor on this PC?
Are all fans working, including CPU fan and video card fan, assuming you have an add-in video card?
Assuming the monitor is ok, if you're using an add-in video card, you may want to remove it and connect the monitor to one of the on-board video ports (DVI and VGA) depending on what inputs your monitor accepts. The on-board video ports are disabled unless you remove the add-in card, so you just can't move the connector from add-in video card to on-board video.
Check the manual for instructions about working inside the PC and removing cards.
Forum Member since 2004
I am not a Dell employee