SD Card Driver Problem

Hi,
I am having a problem with my Ricoh SD/MMC Host Controller and the SD Host Adapter (that is natively installed by Vista) on my laptop. When my SD card works, I can see that both of the Host Controllers are available in the Device Manager, however the next day when I turn on my Computer, both options will dissapear in the Device Manager and my SD Card will not work.
I tried to forcefully install the Ricoh SD/MMC Host Controller again using the "Legacy Driver" option and it gave me a blue screen of death from which I couldn't even boot Windows to safe mode. I then went to "Last Known Good Configuration" and then the Ricoh SD/MMC Host Controller and the SD Host Adapter were back in the Device Manager.
The next day however, the same issue occured in which both Controllers dissapeared .
Why is this happening? I have the latest drivers installed from ASUS (my laptop manufacturer).

PS:
Today in the morning it dissapeared once again, I happened to put my computer on stand-by for a few minutes, and then when I turned it back on, both controllers appeared again . It only dissapears the next day (when I leave the computer off for a very long time), because if I try to restart the computer 10 times, it will stay there.

Can it be, that the power management switch off your device?

Hi,
I don't think it has anything to do with power management because this only affects the SD/MMC Driver. The Memory Stick and xD drivers work perfectly fine and they are all referring to the same device.