I think this is the longest run-on question I've ever seen... you lost me somewhere in the middle, but I'll answer that I've not experienced any runtime issues with Windows 7 with version 10 or 11.
I've set up an SQL request to import training-related data from an external (Oracle) database. The request works fine except that 5 records out of the 54 imported, display the wrong completion dates. In each case the month is correct, but the day and year are not.
I've also tried returning the dates as text with the same result. The same query entered through SQL_Plus returns all 54 records correctly.
Crazy.
There's not a lot to go on here, but there are a limited number of things that update ALL the fields in all your records automatically.
In fact the only thing that comes to mind is an IMPORT which you can set up to replace data in existing records.
If you're not already, you might try opening into a blank layout, just to see if there's something on the initial layout that's messing things up. I recall, for instance, having an issue with radio buttons.