Comcast DVI-D to HDMI cable

Okay here's the deal:


I have an Olevia 232V HDTV

I have Comcast digital cable with the (I believe) Motorola DCT6412 STB


I've been trying to take all the connections from analog to digital, between the STB and the PS2. I purchased component cables for the PS2 and the optical output, so I have progressive scan DVD and digital sound.


The problem is, the cable box is also using the component input on my TV and it's annoying to have to switch the two out each time I want to watch a movie or play a game, and like I said I want the video to be digital. I already have an optical cable for the sound.


So what I did was get a DVI-D to HDMI adapter because the cable box does not have an HDMI output. The main problem I'm having now is that the video is basically blinking between a snowy scrambled screen to a second of the actual channel I'm watching.


Does anybody have any idea why? I called Comcast and of course they didn't really know or help much. They told me to upgrade to a box that supports HDMI, which I didn't even know they had. The problem with this is I'd lose all my DVR recorded shows unless I buy yet another cable (firewire) and try to copy them all to my laptop. I'd rather avoid all that work to be honest, but I might just have to.


Any idea as to what can be done? Or am I pretty much doomed to either staying with analog cables or switching out my box?