You should download the driver again for them and just run it into computer ..The driver it is available on the support site of the manufacturer..
choose teh correct model and the right operation system so that it iwll work proper..
To be sure that the driver it is all you need..just take a look in the device manager ..if the card reader appear under devices but either unrecognized or in yellow with a exclamation sign on it ..it means the devices are working ..but just end the driver ..if you changed the operation system ..you need the drivers for it to match .
by the way ...if you installed windows 7 on 64 ..the drivers should be for 64 system too ..
here are the drivers for this modelhttp://support.gateway.com/us/en/emac/product/default.aspx?tab=1&modelId=1811
download and install the chip-set drivers ..In there should be teh driver for the-card reader too ..
do not be alarmed if the drives are not displayed ..it may be the case that it will display just the one used and when you use them ..Just install the driver s and after that take a look into the device manager and see if they are present there.. to do so click right on computer ..and choose properties and in there select device manager ..If they seam not to be present click right on storage devices..and select scan for hardware changes ..and will add them without driver if they are detected..If no detection is displayed it means the reader is not functional anymore or it cables are disconnected or damaged ..and this is the reason for refusing to load drivers..it simply do not see any device in the system ..
In this case get another card reader or use an external one ..