How to boot an iMac 2008 with faulty Nvidia geforce 8800 GS video card.

And reset the admin password while at it. This will allow you to use the machine using software rendering so you can retrieve your data.

Boot into sing user mode: Option(or Windows key)-S

1. Type fsck -fy
2. Type mount -uw /
3. mkdir /drivers
4. move NV* GeForce*  AMDRadeon*  ATIRadeon* /drivers/
5. cd /var/db
   pwd
   #List all files. The l is a lower case L.
   ls -a
   #The move command acts as a rename command in this format.
   mv -i .applesetupdone .applesetupdone.oldReboot

You will need to replace the video card with the ATI 2600 HD Pro, and manage your heat before you can really use it again. Use (look up fan control?) to make your fans kick in sooner.

This particular video card overheats and unsolders itself. You can also take the video card out and reflow the solder by using oven or heat gun.