I'm trying to run mandrivia 2005 on an older sony VAIO PCG-FX370.
Windows runs fine.

When I start linux if I don't add APM=off it stops durring boot and give the error message: apm: BIOS version 1.2 Flags 0x03 (Driver version 1.16ac)
I turned apm off because I read a thread that said that worked. I have no idea what APM does however.

Now it boots up but the screen goes black when the gnome should start to load. Judging from the computers sounds gnome loads but the screen stays blank.

I can boot into run level 1-4 though so if I need to change a config file I can.

Any Ideas on what's causing the problems?

Maybe you have to add an option at startup (into GRUB?)
I also have a VAIO laptop with some display problems (not as serious as yours though).
In Debian, I add vga=771 as an option in the installer and when booting up and it works fine.
However, I use Debian and it might not work the same in Mandrivia.

dont know if this will help, but i ran across this thread when i was looking for an answer to the exact same problem, im using FC3 with an averatec laptop though. but was having the same problem. i booted to level 3 and edited my xorg.conf file. during install the xorg.conf file had something like
Section "Device"
Identifier "Videocard0"
Driver "via"
VendorName "Videocard vendor"
BoardName "S3 UniChrome"
EndSection

I just changed the Driver from "via" to "vesa" and it booted into graphical mode just fine
hope this helps!

I was going to change the driver like said above but it turns out I have no xorg.conf file. So now I guess I need to create one, but I have no idea how that file is supposed to be structured or everything it needs.

Do you maybe have a XFree86 file? It should be in the same place, something like /etc/X11. the syntax should be the same, so look for that section

nope, no xfree86 config file either. I looked all over for it. Could someone maybe post theirs and I could just paste that into a xorg.conf file?

Maybe try adding a framebuffer option to GRUB. This also solved my problems. Add 'fb1024x768' or 'fb800x600' (no quotes) to the options. Again, I do not know if this is applicable for Mandrivia, but you could try anyway.