Total noob here so proceed with patience.
 
Dell XPS 8700 i7 3.4 GHz 8G mem running W7
came with a Geforce GTX 645 oem vid card
 
Purchased a EVGA GTX 970 FTW+
 
Installed - black screen - booted
Re-seated the board - black screen - no boot (but probably because it went to the DOS error screen - but then who knows, I couldn't see it).
 
Re-installed GTX 645 ... and here we are on this forum post.
 
If you've arrived at this point, please reread the first sentence. And thanks in advance for your assistance.
 
One side note for EVGA - While every consideration can't be covered in the material shipped, it would be nice if you'd pointed out that hooking 2x6 pin power leads needs the adapter that runs it into the 8 pin connector to be used. Having just pictures of the connector does not convey information (even if they do say it's worth 1000 words).

Since there is a little confusion with the cable adapter I just want to make sure you realize that you will need BOTH the 8 pin and the 6 pin plugged in to give the card full power. If you just adapt the 2) 6 pins into the 8 pin but do not use a third 6 pin on the card itself then you will have problems.
 
http://www.geeks3d.com/public/jegx/201003/gtx480_pci_exp_power_connectors.jpg
 

most xps 8700's come with a 460w psu w/only 2x6pin connectors.  you might have to take antrip to best buy,  frys to get a more up to date power supply since the ftw+ needs a 6pin and a 8pin aux connections. 

Once you get that 8-pin adapter installed you might be OK.

 

As mentioned above.  If you use the two 6 pin to 8 pin adapter you must have Three 6 pin cables from the psu.  Two 6 pins into 8 pin, 8 pin to card, one 6 pin from psu to card. 

I think the card comes with a molex to 6 pin as well.  Use the two 6 pins for the 8 pin adapter.  Then use the molex to 6 pin adapter into the 6 pin on card.  If you do not have enough cables need to buy a new psu.  probably should anyway if having to use all the adapters.
 
I am slow at typing, DA beat me to it.  His pic posted shows using the two adapters, lol

Somehow, this is getting to be a little clearer and I thank you for that but to be sure we're on the same page, let me repeat what I think I'm understanding.
 
Since I have ONLY two six pins available coming from my PSU - this is NOT going to suffice in running the board. I would need either another six pin or 2 'molex' 4 pins available which I do not. AND let me pile on by adding that while I said that the PSU was a 500W unit (I was misinformed by someone helping) it is, in fact, a weak sauce 460W max unit.

The BIOS is up to date.
 
So I'm going to say at this point I package this beast back into it's container and ship it back to Amazon. (sad face).

Yes DA74, that is the picture I finally see painted on my wall of reality. I will look into what Dell might be able to offer with regards to a new PSU before I ship back the unit to Amz.
 
But I still maintain that this was a hard place to arrive at considering the documentation ... and as you can see, even within this thread. Then again, we can blame it on the lack of experience inside today's desktop (NOOB).
 
Just want to say thanks again for those that participated and give kudos to this being one of the best help forums I've participated on if only for the number of people willing to help.

Here is a very reasonably priced PSU for much less than what Dell would ask for a similar unit: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139048
My first desktop PC was a Dell XPS 2400 and the motherboard is a mirror image of what any replacement motherboard would look like. I had to buy a new case and motherboard to be able to upgrade to SLI. The hardest problem you'll have with a new PSU is trying to route the wiring harness exactly where Dell had it originally. This isn't necessary but you do need to keep it neat anyway.
 
EDIT: It's even less at Amazon unless they charge you sales tax: http://www.amazon.com/dp/B00ALYOPSS/?tag=extension-kb-20
 

DA74 - Oh yes, it was a tight fit, it reminds me of .... oh, but I digress. My biggest issue was rerouting just one cable - the dvd drive to the motherboard and at one point I thought I could have used your wife's hands, but then (duh) I unplugged it from the drive side which helped plugging it in under the Beast and getting it into the motherboard - much easier re-plugging it on the drive side.
 
Zuhl - I looked a little at a replacement psu but frankly, as much of a challenge working with plugging in the 970, working with an entire set of wiring harness just seemed to be pretty intimidating. Dell was NO help and the referrals they gave were bogus at best. Now, if the PSU only had ports (like the 970 card) to plug the power requirements into rather than the other way around, that would be a PSU that was user friendly - eh maybe not since looking at the current PSU I see where there are varying conditions on each of those wiring sets, though one would suspect that having a certain size plug/type would help remove that obstacle. I'll still look at what they offer but I'm not holding my breath.

No need to buy a new psu. Just buy a 6-pin to 8-pin adapter. Done.
 
Only buy the adapter if your psu is a high quality unit.

The PSU on my computer comes with two - six pin connectors. Your impression is correct.
Sajin, the issue is, I need to plug two six pins into the 8 pin adapter apparently PLUS one more six pin into the six pin connection. Total of three of 3 six pin connectors needed. (wish I could draw you a picture but my 1000 words are below).
 
six pin from PSU into a six pin to 8 pin adapter + another six pin from PSU into the SAME 8 pin adapter - the 8 pin adapter cord has two six pin plugins (like a Y splitter) - and that adapter goes into the 8 pin connector on the GTX card
Plus ANOTHER
six pin from PSU - into six pin connector on the GTX card
 
I apologize for my lack of proper terminology but I plead NOOBism.

Also be aware that the Dell 8700 does require a BIOS update to run a 900 series video card, we have a FAQ about that here: http://www.evga.com/support/faq/?f=59550 

6-pin to 8-pin adapter info:
 
http://www.jonnyguru.com/forums/showthread.php?t=7212
 
http://www.overclock.net/...-pin-to-8-pin-adapters