|I thing Micjlink that if the system has no Service Packs or just SP1 then SP2 or SP1a must be installed before SP3. |
I suspect that is becasue SP1a contained a update that removed the MS Java Virtual Machine as a result of Microsoft's dispute with Sun Micro Systems. . SP2 probably contains the code but it was left out of SP3 on the not unreasonable assumption that it was a waste of space to keep inserting code to remove something that no longer existed So in order to remove the Java Virtual Machine, an earlier update must installed before SP3.