Hello.My HP F2105 21" Monitor screen was coming on for a few seconds then going black/turning off.The blue power button was staying lit though.Well,I found the problem and wanted to share it with others who have this happen.Its the BACKLIGHT INVERTER BOARD.An UPGRADED BOARD is now available.It costs $89.99 and is very easy to replace.They even explain how to do this repair on the website.They also sell replacement polarizers if you have lines in your screen.They also will repair these for you,if you think you can't do this yourself.I replaced my inverter board in 1/2 hour myself and now my HP F2105 is working great again!
Here is a link to their website and a link to the part you need to fix your backlight.The company is MoniServ out of California and they sell other parts as well.Hope this helps anyone fix their monitor.
http://www.moniserv.com/
inverter board:
http://www.lcdparts.net/DesktopInverterDetail.aspx?InverterOriginal=48.L1S04.A01MSS