i have a second HD, when i first used it i partitioned it into ntfs and ext3.
i used "data lifeguard" which came with western digital's HD.
i never used ext3 partition and now i want to remove it and convert it
to ntfs. but in windows, i cannot even see that partition. i failed to run
pqmagic as it said something wrong with partition table or something
like that. if i run "data lifeguard", i could not repartition it.

so my question is: how can i handle this problem? install other partition
tool? or how can i do it in linux?

since i have a lot of data in the drive, i wish you could give me
some details such that i won't screw it up.

thanks very much for your help.
Happy New Year!

AFAIK you can not convert ext3 to NTFS without data loss. You can read the drive via explore2fs in windows and copy the data to another storage medium. Convert the partition and then copy the data back.