SD cards are locking me out? HELP!

I am having issues with my SD cards all of a sudden. I did check the lock on the SD cards and the tabb is not locked. What happens is I take pictures with the camera or transfer pics to be developed but I can not remove the pics I can select all and when I right click the only option I have is to copy them and not remove them.

I have tried defraging but the computer wont do it . I purchased anothr card figuring that the old SD cards were bad and the same thing happen. But if I take the new SD card and place it on my Acer one with Xp windows it will allow me to remove the pics from the new SD card and not the older ones.

Did I select some sort of wierd setting on my computer and not ever relize it. Its really frustrating becouse I need at least one sd card for back up when I go out shooting.

Any input would help Thanks

can u delete them from your camera? like one by one? after u have what u need try to reformat the card i think its FAT32?

I am able to reformat the card on the camera I am taking some pics later and will see if that worked. Dont understand though why a brand new 80 dollar card wont work on my vista seetup but works on my xp set up