Monitor says no signal at startup

hello. Having problems getting my computer to start up. here are the specs:
processor:AMD Athlon 64 x2 2ghz
graphics:NVIDIA GEForce 6159 LE
Motherboard has integrated video card..
One day I went to turn computer on and the monitor said no signal then turned all black with orange light.I can hear the fans turn on but nothing on screen.Doesn't beep at start up and usually right when i turn it on fans are loud then they quite a bit but they're staying loud now.Someone suggested removing the lithium battery in motherboard then waiting a bit and putting it back in. This worked great,computer worked great for about a day then problems started again.Removed battery again,put back in,worked like last time but problems returned.Tried a third time, this time did not work.I bot new battery thinking maybe the old one was dead,still didn't work.any suggestions would be greatly appreciated.I have lots of files and pictures on this computer that can not be replaced.herboard: has integrated video card