Okay here is my two cents.
The problem with the intermittent lock ups is similar to a problem I had recently. I had xp installed and it was showing symptoms similar to yours. I reformatted and installed Windows 7 because I wanted to be lazy and just start fresh then trouble shoot possible software problems, but the issues only got worse.
I tested RAM with memtest 86+ and it checked out fine. Tested HDDs with read/write testers. No problems there. Thought it might’ve been the cpu but didn’t really decide to try another one because I lacked extra thermal paste.
After running all these tests I decided to monitor the system with the resource monitor (ctrl+shift+esc and then click resource monitor button). It seemed fine sitting idle, no problems, but when I ran programs and used the system, my HDD activity meter would spike whenever it locked up. The spikes though, when hitting 100%, were WAY below the rated speeds for the HDD. I grabbed a spare drive and threw XP on it and the system runs like a champ, no problems. I tried formatting the drive that had windows 7 for kicks and giggles and it wouldn’t let me format. It kept failing.
If the problem persists after you switched the SATA port, it MAY be your HDD. First though see if it is your cable by switching to another one if there is an extra SATA cable lying around.
Your video issues are interesting though. If I understand correctly, you had Windows 7 installed once and using the drivers provided on the cd, everything worked fine. Then you reinstalled Windows 7 and tried to use the drivers provided and now you can’t get your proper resolution to stay?
Not trying to insult your intelligence, but do you have your monitor plugged into your motherboard (if it has onboard graphics capability) or your video card. Sometimes it’s the little mistakes that drive people crazy when the fix is something as simple as making sure the plugs are in the right places.
Anywho, hopefully this info will help you out and at the very least point you in the right direction.