Black screen with ATi Radeon 9600

Hi to everyone,
this is my first post. I hope this is the right thread for this question. If not please excuse me. :-)
Since 3/4 weeks ago, my 19" 4/3 CRT monitor started going black for two/three seconds.
Moreover, some of the times I switched off and rebooted the PC, the monitor did not switch on from power off state.
As this behavior of the CRT monitor got worst and worst, until it never switched on again (sob!) I purchased a brand new 22" TFT monitor.
At the beginning everything went well. Now the "once in a while" black screens spreaded out again.
I'm sure the old monitor is broken, but I'm afraid that also my videocard (Sapphire Radeon 9600 Atlantis AGP 256MB) is broken too.
The malfunctioning does not seem related to the resolution (1600x1050) or which one of the two video outputs I use (DVI or VGA) or hw acceleration on/off.
Some of you has any ideo of what I can do before buying a new VGA card?
Thanks in advance,
Luca