1. Monitor bad. Try another monitor and see if it works correctly.
2. Video card bad. Try another video card (that's much more work than a monitor!)
3. Power-saving settings. Those should only apply if it goes black after a certain time (15 minutes, 30 minutes, whatever the setting is) of inactivity. You don't tell about that, so I thought I'd mention the possibility. There's nothing wrong with a monitor going black if you don't use the machine for a certain time.
HP broadband connection Windows XP Sp2
remember we thought it may have to do with memory? But, it has done it 3 times now today...so...is it memory? Is it the monitor? I checked the cables to and from the monitor..they seem fine...is it something I have no clue about???? I need to some someone who can come here and check this out.