alcheryong76, yes, although the G20CI is a unique system, you may want to go with a more standardized system next time if it makes sense.
Also, not sure if the issue is really a problem with the vga card or not (I assume you can still boot to Windows and see the desktop?), but if you think it's worth your time and trouble, thought you may just want to check with your local ASUS support/repair to see what it would take to get your out-of-warranty system checked or running again just to confirm it will not be worth it or they don't have better options to offer you assuming you purchased the unit locally.
The ASUS global website specs will list the cards we ship with the G20CI, but since it is a gaming system, there haven't been any very low-end cards that are approved although I'm not sure what happens if you try them, so may still be worth looking into if it will not be too big of a deal if it doesn't work.
Unfortunately, ASUS has very limited information about upgrades in these systems sold complete and we just approve what we sell with the systems and repair whatever is broken, so you may want to check around more with other people or places.
As far as the PSU goes, expect your system came with both the 180W and 230W power supplies to use with the GTX1070, so you should already have the maximum power configuration.
Don't expect it will be as much of an issue with lower-end vga cards, but you can see higher-end cards in at least a couple different cooling designs where one design blows out the hot air through the back of the case and another blows it back inside the case and lets the system blow out the hot air.
We also use a proprietary vga card design for the G20CI, so you do need to be a little careful about the dimensions of the card you will replace it with and make sure it will fit okay (as well as make sure you have the correct power connections for the vga card which should be more of an issue with higher-end cards) which hopefully will not be as much an issue with a lower-end card .
Anyway, it can be a good idea to take apart the system if you are able to safely and get a good idea of the type and size of card installed in your system before you look for a replacement.
If it makes sense, you may want to find a local store to help find, test, and install, a card for you that works if you would rather not spend the time and trouble, but expect you have less to worry about going with a lower-end vga card.
Just a reminder that ASUS doesn't approve customers to disassemble the unit, so if you are concerned about anything going wrong, suggest taking it to someone you trust (I may be a bit of a worrier, but don't want customers to get into trouble and will probably not be able to help very much from my end if something does go wrong), but you should be able to find some videos online although they may be for a different G20 model rather than the G20CI, but will hopefully be close enough.
If you check the sticky thread copied below in this sub-forum, there is some information from a customer about the G20AJ which again is a different model, but can hopefully give you a good idea what is involved.
Good luck!
https://rog.asus.com/forum/showthread.php?91548-Updated-Asus-ROG-G20AJ-Video-List
