Strange problem with a monitor
 

So I've been using this Dell Inspiron 530 connected to a Samsung flatscreen monitor for about 8 months, which was no longer adequate for my needs so I ordered a new one (but not a Dell) which I now connected it to that monitor.

The plan was to connect the Dell to an old NEC CRT monitor, but for some reason I can only run in Safe Mode. What happens is as XP Pro boots up, the desktop is displayed for maybe 30 seconds then crashes which at this point I can select to restart in Safe Mode.
I did go back and reconnect to the flat screen to see if it still works which it does.

I also had the new computer connected to the CRT for a day or two, til I got it set up and it worked fine.

What would be causing this?

The CRT, like duh!

No clue really.

sounds like your video driver is messed up