Installing Windows SBS 2003 Sp1

Hello,

We have a client running Windows SBS 2003 Service Pack 1 (OS)

Our ultimate goal is to get Windows Service Pack 2 installed, so that they can take advantage of a new backup solution. However, we noticed that SBS sp1 has not been installed.

I discovered and read the following link: C:\Documents and Settings\Administrator\Desktop\ToDownLoadFilesandReadInstructions.htm

Which provides instructions for installing SBS sp1
Download and save the following updates into the SP1 folder:
1. Windows Server 2003 Service Pack 1
2. Windows SharePoint Services 2.0 Service Pack 1
3. Exchange Server 2003 Service Pack 1
4. Windows XP SP2 for Client Deployment
5. Windows Small Business Server 2003 Service Pack 1

Windows Server 2003 sp1 is already installed
Sharepoint is not listed in Add Remove Programs, but there is a Microsoft SharePoint Administrator interface. I have no idea if WSS is installed for certain, and am not sure how to find out.
Exchange is 6.5 (Build 7638.2: Service Pack 2)
Windows XP SP2 for Client Deployment was installed
BPA says Small Business Server 2003 Service Pack 1 is not installed

Having never done this, I must confess that I attempted the Sharepoint update, but it failed (I don't recall the exact error, but it could not find the correct version)
I bypassed the Exchange update
I installed the Windows XP Sp2, which was successful
and I attempted the SBS 2003 sp1, which seemed to go well (took a while) until the end when it generated an error, and yet presented the Finish dialog box and then indicated the install was successful. After a restart, it appeared that the install was going to continue, but it failed.

Do I try to run through all five updates, even though Window Server Sp1 is already installed and Exchange is already at sp2? How can I tell if SharePoint is truely installed, and what do I do if it is not?

I am at a loss of how to proceed.

I am grateful for any assistance.
Linda