CAn't install windows 2000 SP4 on computer...

[emnsam]

I have a computer that a friend gave me because mine was finished. On this computer came installed Windows 2000 SP2. I have tried updating this to SP4 from the microsoft website, but it just won't install. If I save the download, it just goes on my desktop and when I open it, it says that it's extracting the files and then nothing happens. When I say open instead of save, it downloads, installs and then asks me to restart, but then when it re-starts nothing has installed. So all the critical installments that were suggested by the Windows update are not installed, neither is the SP4. I tried doing them one by one and still nothing. Also, when i re-start the computer, at times I get a message that explorer.exe has caused an error and needs to re-start, so I am stuck re-starting the computer several times before it uploads properly. Any suggestions? (other than buying a new computer)
Thanks.

[MrChris-]

Try to download it from Microsoft directly instead of auto update and then install it. This may help you.
Download it here - Windows 2000 Service Pack 4

Description

Windows 2000 Service Pack 4 (SP4) provides the latest updates to the Windows 2000 family of operating systems. These updates are a collection of fixes in the following areas: application compatibility, operating system reliability, security, and setup. Windows 2000 SP4 includes the updates contained in Windows 2000 Service Pack 1 (SP1), Windows 2000 Service Pack 2 (SP2) and Windows 2000 Service Pack 3 (SP3). If you have already installed a previous service pack, download and install SP4 without removing the previous service pack. Microsoft considers Windows 2000 SP4 to be a recommended upgrade - especially if you don't have either SP1, SP2 or SP3.

If you install SP4 over Windows 2000 Service Pack 1 (SP1) or an earlier release of Windows 2000, your computer will automatically be upgraded to 128-bit encryption to provide better online and local security and to bring your computer up to the current worldwide encryption standard. Beginning with Windows 2000 Service Pack 2 (SP2), 128-bit encryption is supported as the default, so if you previously installed SP2 or Windows 2000 Service Pack 3 (SP3), your computer has already been upgraded to this level of encryption. Important: your computer retains 128-bit encryption even if you revert to Windows 2000 or SP1 unless you reformat your hard drive and complete a new installation of Windows 2000 or Windows 2000 with SP1.

For more information about the fixes in SP4, see the readme that is in the download - it can extracted with a zipping tool.

Instructions

1. Click the Download button on this page to start the download and click Go.
   
   
2. Do one of the following:
   
   • To start the installation immediately, click Open or Run this program from its current location.
   • To copy the download to your computer for installation at a later time, click Save or Save this program to disk.

[newtech]

Generally reinstalling windows on top of the current OS should solve the issue

Also try copying explorer.exe from some other machine and put it in yours

[Zachary]

No original/legitimate CD's for software? I can't imagine another reason and that may well be what it takes to fix this!

[SalVatore]

How are you verifying if the updates are installed or not? You can right click on My Computer and check in the properties what OS and Service Pack it is showing.

It can be that the service pack and other updates are already installed at the first attempt and now they are getting over written every time you install them and you are not aware of them.

This is just a doubt that I had because 1 of my friend was worried with the same situation and then he realised after verification that the service pack is already installed and he was just over installing it thinking that it is not installed.