0:Try to avoid flashing the bios on battery power. Also don't even try it if you don't know what card revision you have.
1:if you have bios version 188.8.131.52.13 then its a rev0, if it's something else then you have a rev1. (You can find this on advanced tab in display properties. If you are using the new control panel don't open it, just click on the "Geforce go 7900GS" menu tab on the left.)
2:Use disk burning software (such as nero) and it should be something like "Burn image to disk" or "burn iso to disk"
3:Ok this one is harder but the following should help:
If you just want your card to be the same as stock except with unlocked clocks, use the unlocked, not memory optimized, 1v bios. (clocks ~470/600 at best)
The memory optimized bios loosens the memory timings on the video card so you can clock the memory higher. (clocks ~470-850 at best)
NOTE: The voltage (1v or 1.24v) has no effect on memory clocks.
With the increased voltage but no memory optimizations the core can now be clocked much higher, but your temps could go above 90 with higher clocks. (clocks ~620/600 at best)
The best possible performance is with the memory optimized 1.24v bios. This can cause high temps, but could result in 10k+ 3dmark05 if you have a good card.
NOTE: The 7900GS rev1 bios does not have memory optimized variants.
4: The only reason you would need to edit the bios in nibitor would be if you wanted to mess with the delta offset but that's a more advanced tweak.
5:The card will clock down on battery as long as you leave the nvidia display driver service running. (The stock bios will clock down even if the service isn't running.) You can change the behavior of the card on battery in the nvidia control panel. (powermizer)
6: for a normal flash you just need: nvflash XXXXXXX.rom
If you want to flash the 7900GTX bios for some reason (works the same as the 1.24v memory optimized 7900GS bios) then you would need: nvflash -4 -5 -6 XXXXXXXX.rom (note: the 7900GS rev1 won't work with the 7900GTX bios)
7:Useful tools:ATItool, (overclocking/stress testing) I8kfangui (temps/fan control. note: remember to set a +8 temp offset for the GPU) optional: Rivatuner (GPU realtime clock monitor/driver tweaks/overclocking)
8:You would need to make a blind flash disk. There is a great guide here: http://www.notebookforums.com/thread181387.html
9:I personally use the XG mobileforce 92.91G2 driver. It works great and I have had no problems with it. This seams to be consistent with most users.
10: With non optimized memory 600 is about the limit of good stability for most people. With the memory optimized bios the good stability/heat limit is 800.
With 1v you don't have to worry about heat very much so you can go as high as possible without artifacts safely. (usually ~460) With 1.24v 600 is usually the limit for heat/stability. 600/800 seams to be the sweet spot for the 7900GS.
WOW that took awhile lol.