Same problem here, but I did not know the source was an SD card. I simply found one of my 2 CPUs running at 100% and the cause ultimately was ReadyBoost. Disabled it and things are again normal.
May experiment by reenabling it, then inserting an SD card, but it sounds like this problem is generic to Vista?
I also have an iPod, SmartPhone, SD cards, and CompactFlash cards. Any one of these may have been the trigger.
Comptuer is HP Paviliion desktop d4790y wih Core 2 Duo / 2.4GHz.
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