I have found a few problems with Vista MCE when installing video related
programs, for example divx and Nero. The main problem being the ehrecvr.exe
process crashes which stops live TV from working.
Although this is best practice, I would advise that a restore point is taken
before installing any such software and if possible depending on your version
of Vista, take a full image backup.
The latest nero version - 7.7.5.1 - does allegedly fix this, but I have still
experienced some problems with the full suite of software and scaled back to
only install the Burning software.
By having the backup, if something does fail, it is easier to resort to an
earlier version of Vista rather than having to reinstall Vista.