1. Go to Start > run > type "diskpart".(Without Quote)a dos window will appear with following prompt.


DISKPART>

2. Then type "list volume" this will look like it

Volume### Ltr Label Fs Type Size Status Info
-------------- ---- ------ --- ----- ---- ------- --
Volume 0 F DC-ROM
Volume 1 C NTFS Partition 7000MB Healthy
Volume 2 D soft NTFS Partition 8000MB Healthy
Volume 3 E ---- NTFS Partition 8000MB Healthy

3. If u wanna hide drive E then type "select volume 3"
then a message will appear in same winwods { Volume 3 is the selected volume}

4. Now type " remove letter E" now a message will come { Diskpart Removed the Drive letter }sometime it requires the reboot the computer .

5. Diskpart will remove the letter .Windows XP is not having capabilty to identify the unkown volume.

Don afraid ur Data will ramin same . To Come backe the Drive repeat the process . but in 4th step whish is shown in this post replace " remove" to "assign"i mean type " assign letter E"