...Internet explorer won't open the updates catalog so how can I update this machine?
Welcome mr_video!
If IE is the only browser on the machine, then you will have to use another machine with a decent browser to download installers, then transfer installers to the Server 2008 machine using removable media (assuming USB or optical drive are usable).
Without delving into the realm of fringe browsers (developer projects which are the last hope for Windows 6.0 and older),
Firefox ESR 52.9.0 x86 was the last decent browser for Vista and presumably worked on Server 2008 as well. Select the language you want at this
Index Page (in my case I would choose en-US, but you didn’t select a national flag for your forum account), then download the offline installer. (Even if your Server 2008 is x64, do not search for an x64 build of Firefox ESR 52.9.0 because it required Windows 6.1 minimum.) I’m not absolutely certain that this browser would still work at the catalog, but it did at least support TLS 1.2. Perhaps
@wither 3 could confirm if he still has Firefox installed on his Vista? Here’s a download link for
Service Pack 2. (Note: There was no SP1 for Server 2008 because the initial build was 6.0.6001 like Vista SP1. There was an SP1 for R2, but that’s Windows 6.1.)
I don’t think anyone here has actually used Legacy Update, but let us know if you have any success with it. There was an MSFN thread in which Windows XP users reported success with it, which is probably where SIW2 first heard about it.