Driver will not load - Windows7

[evanr]

I received a replacement Arduino board and switched it with the old one.
But, windows7 can't find the driver (even though I d/l it from frdichip.com/Drivers/VCP.htm).

The driver install manual says I may have VID/PID entries which don't match.... from the manual: "This error can occur if the VID and PID programmed into the device EEPROM do not match those listed in the INF files for the driver."

It seems the new Arduino board is not compatible with my system?

now what do I do?
Anyone had this problem?