no video signal from graphic card

[sujeet2555]

my pc config;
Processor: AMD Phenom X4 9650
Memory: 4096 MB DDR2
Graphics :NVIDIA GeForce GTX 560
onboard graphic :ATI Radeon HD 3200 Graphics
Motherboard : ASUS M3A78-EM Rev. X.0x
Disc :Seagate ST3500418AS 500 GB SATA II
Windows : Windows 7 Ultimate 64-bit

my graphic card is new .this problem happens to start from the time when it was brand new.i installed the graphic card ,plug the crt monitor into GPU with the DVI adaptor. changed the setting in BIOS as GFX-GPP-IGP-PCI .on first start no video from monitor .so ,i thought DVI convertor was loose ,so i reconnected it .after some tinkering ,video came on.
now my PC was idle for one week and after one week i am getting many BSODs like ;7E ,7F,F4,1E .it was running fine one week before.
1.Bugcheck code: 0x1E (0xFFFFFFFFC000001D, 0xFFFFFA8006808B60, 0x2, 0x0)
Error: KMODE_EXCEPTION_NOT_HANDLED
file path: C:\Windows\system32\ntoskrnl.exe
2.Bugcheck code: 0x7F (0x8, 0x80050031, 0x6F8, 0xFFFFF800036C6812)
Error: UNEXPECTED_KERNEL_MODE_TRAP
file path: C:\Windows\system32\ntoskrnl.exe
3.Error: CRITICAL_OBJECT_TERMINATION
file path: C:\Windows\system32\ntoskrnl.exe

i ran memory diagnostic successfully without any error.SFC with no error.CHKDSK with no error.
sometimes pc doesn't start (it doesn't give any beep ,only fans running). after getting rid of BSODs ,this problem has arisen .why i am not getting video signal from the graphic card instead it is giving out from onboard gpu.sometimes it start giving out from gpu but i don't what is the cause of this ? how do get rid of this annoying problem.

 

[harshilsharma63]

Reset the video adapter setting you changed in bios to default. The motherboard automatically enables the discrete gpu in its presence, no need to do it manually.

 

[sujeet2555]

Reset the video adapter setting you changed in bios to default. The motherboard automatically enables the discrete gpu in its presence, no need to do it manually.

the setting was done only when it was installed new.after that it was running fine.only sometimes it don't give output then it came back after some tinkering.i don't know really what fixes this problem .

but it has configuration options as follow;
1.gfx-gpp-igfx-pci
2.gpp-gfx-igfx-pci
3.pci-gfx-gpp-igfx
4.igfx-gfx-gpp-pci

 

[whitestar_999]

what power supply are you using & i hope it is not some local/indian cheap brand?

 

[sujeet2555]

power supply is corsair430.
BTW after 2 days of work ,i think i solved the problem .the GFX card need two PCIE power supply .one of the connector was loose such that one pin came out of the connector when push on to the gfx card.
does this was the culprit of BSODs also ? like gfx power supply cut off when running so giving these BSODs.
i will reply again if i gets this problem again.