Here is my computer setup From Windows

31MB Fat Primary Partition Dell
24.94GB NTFS Primary Partition
Might be swap 102MB Primary Partition
Extended Partition 2.87GB
1 Logical Drive

24.94GB NTFS Primary Partition Resize this

I am thinking its 4

Number/Partition/Type/Size
01 /dev/hda1 Fat16 31.35MB Primary Partition
02 /dev/hda2 NTFS 24.94GB Primary Partition
03 /dev/hda3 ext3 101.97MB Primary Partition
04 /dev/hda4 extended 2.87GB
05 /dev/hda5 unknown 2.87GB

That unknown is LVM in Fedora Core 4

Also Do Extended and Swap count as Primary

I don't know the underlying reasons, but yes, a hard drive is limited to 4 primary partitions.

I also believe that an extended partition itself counts as one of your four primary partitions. Its primary purpose of course is to allow more than 4 partitions per drive.