I'm sorry to hear that you're having issues with your 2494HS.
Unfortunately, outside of checking the cables and the power supply, there's not much that I can do to help troubleshoot the issue.
However, it's likely under warranty and can be repaired. You can call 800-SAMSUNG or fill out the online form here:
I have a Samsung SyncMaster 2494HS LCD display.
Today during normal use it blinked once then the backlight just switched off.
If I turn the monitor on and off again, it lights up as per usual and stays lit for about 2seoncds before dying again. If I hold a LED keyring-light close to the screen I can see my computers display there, but it's just not being lit at all. It also does the same thing if I switch over to the HDMI input (stays lit for a second then dies).
Less than 9months old, haven't had any issues with it.
Thanks for any help.