I am following instructions on dividing my new 30 GB HD into 10 GB partitions.

So I made the Primary partition 33%, the same with the Extended partition and then the Logical DOS drive.

But it doesn't look right becasue the Primary Dos partition is "C:" the Extended partion has no letter and the Logical is "D:"

How do I divide my HD into neat sections with C:, D: & E: with each partion being 10 GB?

I tried making the extended partition smaller but this made the data available for the Logical partition smaller too.

The middle partition is probably seen as unallocated space. Did you format?

To change drive letter assignments for XP (I'm assuming XP) look at MS's instructions here. (http://support.microsoft.com/default.aspx?scid=kb;en-us;307844&sd=tech) Heed their cautions.

The extended partition is not given a letter; only the logical partitions within it are given letters.
Hence, you should make 2 logical partitions [within the extended partition] and these will be given letters D: and E:

I advise you to make a smaller partition for C:
Keep only the "Windows" and "Program Files" [plus odds & bods] on there.
The needed size depends on which version of Windows and how many Prog's.
I have Win98 and 50+ progs and my 3,000MB Partition holds only 1.57GB.
Because it's small, [program] files can be found quicker, it's quicker to defragment and make backups and restore, and the backups use less space in storage.

I move the following onto a small D: partition. Mine is only 2,000MB.
Thus, when the C: partition is restored to eliminate a software problem these remain untouched and up-to-date.
a. My Documents. [Use “TweakUI” to move their home]
b. E-mails for all identities. [use the email client to move their home]
c. Internet Explorer Favourites. [Use “TweakUI” to move their home]
d. Temporary Internet Files. [use the browser (Internet Explorer) to move them]
e. Re-home the Windows Address Book as shown here http://tinyurl.com/24q6l . Use the key “HKEY_CURRENT_USER\Software\Microsoft\WAB\WAB4\Wab FileName” to specify its new address. [Its normal home address [in Win98] is C:\WINDOWS\Application Data\Microsoft\Address Book\(the name you gave your PC).WAB]

Additional partitions should be used to hold different types of data according to typical file size.
If you're using FAT32 partitions, large clusters should be used on partitions where you plan to hold large files, and small clusters for small files.
I have C: & D: using 4kB clusters, and E: & F: using 32kB I think.
The idea is to match the contents to the container size.
The number of clusters needed to hold a file should be more than a few, but not too many. Perhaps 10 clusters to a file, not 10,000.

You will see the number of clusters [the little rectangular boxes] occupied by each file when you defragment. Some files will occupy [less than] a single cluster. Perhaps only 1kB is occupied. If it's a 4kB cluster, then 3kB is empty [and wasted, unusable] space. That's 75% "slack".
On average, 50% of a cluster is "slack" for every file, and total slack is the total number of files multiplied by half the size of a cluster.