What happens when you DON'T install the updates? Many updates are really not necessary at all to some people. Since i do not use media player i do not even install any for it. If you can find out the KB numbers for each update you could install each one, one at a time to see if that one caused the problem. Then just do not install that update. This is supposing that you can start XP now, if you do not install the updates.
msxml3.dll is usually for the net framework files.
urlmon.dll is associated with Internet explorer and also Microsoft Office.
winhttp.dll is windows HTTP services( for Internet Explorer).
shell32.dll is part of the Windows operating system, and the exact file location is listed below. The shell system is important for handling many windows tasks, and is required for your system to be stable. This file is not known to be spyware or adware, although you should always verify the location to make sure the name is not being copied and placed elsewhere as spyware, to make it look like the same program. shell32.dll is found on your hard drive at C:\windows\system32\shell32.dll. If it is found anywhere else on your computer it is spyware and steps should be taken to remove it from those other locations.
It may be spyware that is causing you problems with your updates. you might check in at the malware forum to make sure your computer is clean.
then start here if you have any questions.
Last resort is to do this for computers i work on.