Graphics card not working and onboard graphics not starting

I took my heatsink off to clean it for dust and reapplied thermal compound. I seem to have done that part right since my core temperatures are down (it barely touched 50C during a 15 minute CPU Stab test and that's in a warm room) but my graphics card isn't being detected and my onboard graphics isn't starting correctly (according to the device manager). When the computer starts it gives a message to the effect of "didn't post correctly or last boot failed". As far as I know I didn't go near the graphics card and it is definitely still receiving power as the fan's still moving. I haven't used the compuer in months but the last time I used it the graphics card was working.

Any ideas as to how I should proceed? My best guess is that I misapplied the thermal compound (it was my first time and it did not go smoothly) and have damaged the north/southbridge (whichever connects to the GPU).

 

You may have bumped your graphics card and it may need reseated.

 

Second Just Playin's advice. Most of the time this is the issue.

If re-seating the card fails to correct the problem, make sure you didn't unplug a power cable from the card (if it requires one).

Boards of at least the last 10 years will auto-switch to an add-on video card when one is installed, or vice-versa. I have run into a few boards where you have to manually change the setting in BIOS.

 

I really didn't think that would work because I hadn't touched the graphics card but it did. I'm not sure that the graphics card hasn't been damaged because the process didn't go smoothly (I had to have someone hold the case down!) but it appears to be working.