Video issues can be a real pain. I'd try the easy stuff first. You'd said you "upgraded to W7-64", but you didn't say you'd done so from a fresh OS install. (Is it possible to try to change the OS when migrating from a HDD to a new SSD?? I'm probably old school, but I'd never try to "upgrade" the OS... and any "migrating" I might do would have to be via cloning or image restoration on the same machine.)
hmmmm....I installed W7-64 on a used hard drive which was reformatted. I reformatted the drive (wiped XP off the drive), then installed Windows 7. Not a XP upgrade to Windows 7, if that makes sense?
Here's a possibility. When Vista came out many of us didn't want to keep it... preferring XP. But reformatting a Vista drive didn't work like we'd hoped. Seems the Master Boot Record didn't get overwritten in the reformatting. The solution was to run a Low Level Format... which also overwrites the MBR... then, fresh format/install of different OS. Ever since that experience with Vista, I automatically run LLF on any drive where the OS will be changed... even when changing W7-32 to W7-64. Not 100% sure I always need to do that these days, but I do it anyway.
Can't blame you there... but if the problem is with old schmutz on the drive, new video cards won't help. If you've got a spare drive laying around, you might try LLF + fresh W7-64 install. There is still the possibility your W7 just doesn't "like" the monitor you have in the primary position in a 4-monitor setup.... has happened to me.
Do a search for "Low Level Format 4.25" (later versions have bundled software). It will run at 50Mb/s unless you buy the upgrade. Upgrade is only $3 and will let your drive write as fast as it's capable..... it's worth the $3, especially for SSDs. Mount the drive to be LLF as a secondary (the program won't LLF the boot drive so users don't screw themselves up). Then run the program. I've used it lots of times.
Sorry, gentlemen, it's a waste of time. LLF is not the most optimal way to rewrite MBR, and reformatting MBR is not going to make the video issues go away.
Old MBR information could be corrupting the behaviour of the new OS and making it think it is a ghost of its former self. Sure, every A+ certified tech knows MBR doesn't contain video drivers but stranger things have happened when the OS doesn't know what it is. Scat is talking from experience. Though, I am afraid this OP will turn the drive into a paper weight. Happens to the best of us.
1. I don't know the "optimal" way to rewrite the MBR, but LLF does work. At least it assures you're working with a clean slate. 2. Rewriting the MBR may make the video issues go away. We're troubleshooting here. Every possibility is to be explored. Hopefully your first try/guess is correct. Usually it isn't.