Vista & XP Upgrade Questions

[nfountai]

2 Questions
I've been reading these post and was wondering.
My new laptop for home is a Vista and my older Hoster program freezes when I click on a song. Hoster is 3.321 as I just upgraded from 3.316. I did all the suggestion that MTU told me to do to the Vista machine and Hoster still stops working when I click on a song. It goes to"CUE" and that's it.
The latest email from MTU tells me to use 3.316 and it should work, but MTU also now suggest to use 3.321a or 4.008. I can't find 3.315 or 3.321a on the web site. I see Hoster 4.008 and if I buy it, do I buy just the upgrade as I am a current Hoster user? I get a little confused as which one I have or need to get.

But on my laptop that I use out has XP and Hoster 3.312 which works just fine. So, I was wondering if I order and install the Hoster 4.008 on the Vista machine, will Hoster 4.008 work ok on my XP too?
I was wondering how do I do a search for a song using my XP & Hoster 3.312. For years I keep 2 programs open, Hoster & Kjpro. I also us an external hard drive with my XP machine if that matters.
Sorry, I guess it was more than 2 question, Hum.
Thanks