video card no longer recognized! PLEASE HELP

[briefcase791]

ok. i have an nvidia 7800 gtx 512mb that has been working in my rig for several months now. Windows vista ultimate, forxconn micro atx mobo 4gig corsair ddr2800 ram, 250g hdd, 380w antec psu.
i just bought a 22" acer monitor a week ago.
i turned on the puter from sleep this morning and the computer turned right on, all lights, fans etc on. but nothing appeared on screen. it didnt beep since it was waking up from sleep not off. in my morning grogginess i hit the reset button, it reset, beeped once and turned on but still no picture at all.
naturally i checked all connections and theyre fine. monitor has vga and dvi(using dvi) and i plugged it into the onboard dvi, and STILL nothing. being thorough, i plugged the vga in the onboard and the screen came on. tried the new 22 and an old crt in both dvi and vga and only the vga worked on both.
i checked the device manager and dxdiag and neither even see my video card now so i cant check drivers.
also dontknow if it applies but:
as vista users know, you can change what the power button does and i had it set to put the puter to sleep. in my checks, i noticed that that setting changed to "do nothing" and the sleep option was entirely gone.
maybe windows is corrupted? i hope its as easy as a reformat or something...what's blowing my brain is that the fan on the gpu comes on still. can that happen and it still be dead?

i really hope that my video card isnt dead as i cannot afford another one...
what should i be looking for and how can i see whats wrong?

 

[Soulrak]

Wow, pretty much the exact same thing happened to me yesterday morning. I was on my computer the night before and the computer was working fine. I also got an Acer 22inch two weekends ago. I had about a week with the monitor and it was working fine. So anyways, yesterday morning I turn my computer back on, and no image. I switched the VGA to the computers original graphics card and it worked. I restarted my computer and my custom graphics card still didnt show image. What I did notice is that when I turn on my computer, the fan is on longer than usual then followed by a beep. It never use to do that. I have no idea whats going on, maybe an automatic update from windows? Im not sure. I cant even check the drivers for my graphics card because it the pc doesnt read it.

 

[briefcase791]

crazy. i have made some progress however. my monitor uses both vga and dvi cables. i was using the dvi, but since it stopped working i switched to a vga cord with an vga to dvi adapter since th\\my video card only haas two dvi. what do ya know it, it turned right on! still not 100% sure what happened or if i fixed it, but it is working and the comp recognizes my card again. going to update drivers and everything, see if that helps

 

[Guest]

Wow, pretty much the exact same thing happened to me yesterday morning. I was on my computer the night before and the computer was working fine. I also got an Acer 22inch two weekends ago. I had about a week with the monitor and it was working fine. So anyways, yesterday morning I turn my computer back on, and no image. I switched the VGA to the computers original graphics card and it worked. I restarted my computer and my custom graphics card still didnt show image. What I did notice is that when I turn on my computer, the fan is on longer than usual then followed by a beep. It never use to do that. I have no idea whats going on, maybe an automatic update from windows? Im not sure. I cant even check the drivers for my graphics card because it the pc doesnt read it.

Same thing happened to me. Working fine night before then didnt show image. Same thing with a beep at startup and it taking longer than normal. I noticed that when comp IS reading graphics card it sees 3GB of ram but when its not reading it (i plug into internal graphics for this) it shows 2.87GB. Very strange. Im wondering if it is the adapter being used....? Im using a sycmaster toshiba moniter. So i don't think its just the moniter. Im running windows XP too; not vista... So either a windows thing in general or some setting in the BIOS or an outdated driver. Could it possibly be the moniter? I can't figure it out, been beating my head over and over for this one...