You can do this with a disk utility like PartitionMagic; however, YOU MUST BACKUP YOUR FILES because adding/removing/changing a partition always involves the risk of losing data on all partitions.
PartitionMagic (Symantec.com) is expensive. You could buy a 100+ GB hard drive for the price.
I am using wind xp sp2. There is four logical partition on my 40 MB hard drive. OS is on one of the logical partition D. It is nearly 90% packed.I want to remove the logical partition to increase the capicity of the Hard disk. can i remove the partition without uninstaling or disturbing my installed programmes and operating system.