Why won't my pc read the SD cards I put it?

I have recently upgraded my very old pc but I am trying to edit and read some information I have on some SD cards, including ones on my mobile. The light goes on besides the slot but that's about it. I'm not sure which drive it suppose to correspond but I have tried all of them. I have even used one of those usb adaptors for them but the same outcome still arises.

Why won't my pc read the SD cards I put it?
Do you connect the Card Reader via a USB Port? If so read on.... The Card Reader need power to drive it, if you are connecting the reader via a cable you will get a power drop over the length of the cable which means there is insufficiant voltage to drive the unit. (I had the same problem with an external Hard Drive I was trying to run via a multi-way hub. When I removed the multi-way and cables it worked fine). If you have a light on it means the slot is trying to work, windows should make a noise when it recognises the new Hrdware and the drive should show up as D,E,F etc. If not the Card Reader is not being picked up and that is another reason why it is not working. As you say it is a very old PC I expect the POwer Supply is not strong enough to supply enough power to the USB slots. I would suggest removing all other USB users, remove multi-way and use the shortest cable possible between the conputer and Card Reader to give you the best chance possible.
Reply:maybe the card's locked?
Reply:Did you install the drivers for your reader if not it won't work.
Reply:make sure the button on the side is on the top.