How do you format an sd card on the computer?

When I try to use my SD Card in my computer ...You need to format the disk in drive F: before you can use it?

• I had been using my SD Card to transfer pictures from my Canon EOS 1100D camera for a few weeks now and have never experienced a problem. Then, today I put it into the SD Card slot of my computer (as I always do) and tried to access some pictures I took earlier. When I try to access the pictures, Windows tells me that "You need to format the disk in drive F: before you can can use it. Do you want to format it?" When I go to format it, it says that this will erase everything on it, but I can't have this happen- I took valuable pictures for my photography project. 1. Why is this happening now? The computer has been able to read it before... 2. Can I / how can I fix it without losing pictures? 3. Upon putting it back into my camera, I found that now my camera says that I must change the format of the card, so I cannot even see the pictures there. How can I fix this? Thanks.

• Answer:

  computers are pure stress, one windows update fix and bang! somethings not working. Your best bet is to get a cheep usb reader. This way you plug the sd card into the reader and the reader into the usb slot. Why it's doing this could be down to a card problem, so try using another card. Plus the bios during an update gould have been altered and the sd card slot can no longer recognise the size of your card. ie, it may only read cards under 2gb or less. A usb stick would by pass that problem...