Nvidia GTX 690 weird video issues

Hello,
I just finished a build and for my GPU I went with the GTX 690. Currently I am using the Mini Display port with an HDMI adapter. This is going thru a Bose LS system and into a 55" TV. When I first fired up the system the only port outputting video was the Mini Display Port. Now after about 1 month using the Mini Display port with no issues the video seems to disappear after the windows splash screen (never gets to login). If I take the HDMI off the Mini Display Port and plug it into the bottom DVI w/HDMI adapter the video and sound usually returns (not always the case). One time I had to resort to a DVI to HDMI cable and use the 2nd DVI port and video was back. This can happen while watching a video or even just resizing some open windows.
This is the only setup I have used this system on. It has not seen a multiple display arrangement yet.
The build is as follows...
Windows 7 Ultimate 64
ASUS P8Z77-V PREMIUM MB
Intel Core i7-3770K Ivy Bridge (not OC yet)
G.SKILL Ripjaws X Series 32GB DDR3 1600
SAMSUNG 830 Series 256GB SATA III SSD
ZALMAN CNPS9900MAX-B CPU Cooler
EVGA Signature GeForce GTX 690 GPU
(3) Seagate Barracuda ST3000DM001 3TB 7200 RPM 64MB
Corsair 1200 PSU

A bit overkill for a Home Theater PC but currently thats what I use it for.

Any Ideas ?? Thanks in advance ....