monitor problems

Today I decided to hook up my "shop computor" and save the laptop which
has been running my CNC lathe for other purposes. I loaded CNCPro and
went to run it only to discover that the Dell/Sony trinitron monitor
won't function in MSDOS mode. In fact it only displays when the Windows
98 blue screen appears as Windows does its final loading. No windows
logo or anything other than a clicking that sounds like a gieger(sp?)
counter. Then blink-a fully functioning Windows. I plugged in an old
(out of focus) monitor to see if it was the computor but it funtioned
without problem in DOS mode . Plugged the Dell monitor back in and
nothing but clicking and a black screen. I checked the Windows settings
to make sure that the correct monitor was specified and that it had the
latest drivers. What am I missing here? Works in Windows but not in DOS.
I checked through all of the FAQ's on the Dell website to no avail.
Anyone have any ideas?
The computor is a 450mhz Intel system with a Trident video card. Dell
D1025HT monitor. Carey