Windows 7: New Laptop......

There is a workaround that might allow you to in-place Upgrade HP to Enterprise, but it is not advisable since Enterprise uses volume licensing which is completely different activation method than HP.

So I would do a clean install, which means you can use the install DVD's Custom>Drive Options tools to delete both the 199mb partition and C:, then create a New partition there, Format and install. Back up your files first.

If you decide to keep HP on C and still want to merge the 199mb SysActive Boot partition into it, we can give you the steps to recover the disk space and MBR into C using Partition Wizard CD and Windows 7 DVD or Repair CD.

Is there any advantage to keeping the 199 MB boot partition separate?

I guess it doesn't apply to the Enterprise version but I did an anytime upgrade from the HP factory home premium install to Windows 7 Ultimate which took only a couple of minutes and worked very well.

Unless you use Bitlocker in Ultimate, the advantage of the SysReserved partition is to place "Repair My Computer" on the Advanced Boot Tools menu accessed by tapping F8 at bootup.

If you pre-partition your HD, the installer won't offer the Windows 7 100mb SysReserved partition. Deleting your current 199mb factory Sys Reserved and C may or may not cause the installer to create SysReserved since there is other partitioning on the HD. If you are sure you don't want that boot partition, then pre-partition the deleted space using free Partition Wizard bootable CD: NTFS Primary partition.

Thanks.