I need to use sd card more than 1 G

in the commandprompt:
1.sfc /scannow
2.checkdisk

3.Control Panel - Device Manager - USB Serial Controllers - RIGHT CLICK on EVERYTHING and UNINSTALL
all except the category itself - REBOOT

Hi!
if you want use the 4G you make sure your memory cards is compatible to 4G. then now you have got stuck when you back the 512!? all you have to do is to reformat your camera in to software. Thanks!!!

change sd card or check its connecting pin jack in sd compartment

Are you sure it will accept a 4 G card (presumably you mean 4 GB) ? Some devices are limited in the capacity of the card they will accept.

Might be different format structures (eg FAT, FAT32, NTFS). FAT is most universal within windows and devices.

The 4600 works with SD cards. Your 4GB card is actually an SDHC card. While it fits into the slot it is electronically incompatible and will not work. You need to use SD cards, 2GB and smaller.

That is correct. While SDHC cards will fit into SD slots, they are electronically incompatible. SD cards will work in SDHC slots but not the other way around. You need to go with SD cards 2GB and smaller.

Most likely the phone that doesn't read it and the SD card reader can read "SD" cards but not the "SDHC" that a 4G card will be. All SD cards 4G and above are SDHC, and a plain SD card reader will not read this card.
Buy an SDHC reader, and get a smaller (up to 2G) card to use on the older phone that can't read the 4G one. Hope this helps.

SD cards must be SD not SDHC, there is not an SDHC driver for the X5. You can find regular SD cards up to 4G.

CF is no problem, all flash based CF cards will work. Microdrives can be problematic.

Try opening a terminal (Ctrl + Alt + T) and type sudo bash.
This should give you access to everything.
If this does not work then I am not too familiar with linux either so I probably cannot help.

Mowcius