Can you go from a VGA graphics card to a Display port screen with an adapter?
you can go the other way around - from a display port card to a VGA screen with an adapter, but I've been doing the google and I can not see this question answered anywhere.
The easiest fix might be to get a cheap graphics card...sometimes with rebate, you can get them for $10 or less...they'd have DVI, HDMI, and VGA (sometimes DP). You could use a DVI to DP converter for sure with that.
Just looking a little further...you can get a VGA to DVI or VGA to HDMI converters, so theoretically, you might be able to find one. Even if not, you could convert to DVI, then put a DVI to display port adapter.
The bad news is that the converters are a little bulky (certainly not cable sized) and cost between $50 and $100. I checked monoprice and found a few.
Must be the analog to digital conversion.
Seems like a video card would still be easiest and cheapest, though the other seems technically possible, if a bit expensive and cumbersome.