Win XP is fully supported; it is Vista that isn't.
Another thing: Definitely don't use Java 6, the site locks up. Java 5 (which they give you in the installation instructions) is the latest you can use. And, softconsult is spot on, IE7 and Vista will probably be OK (Java 6 will NOT), but I know they are working on it, since you can't buy a new computer without vista these days...

Finally, this page shows the coverage, same place with the prices.

But, if you have a US version car, everything the dealers can see is also on this site - because this IS the site the dealers use through their star tek info access. Same server and all.

Have fun all,

Newbie
PartsGuy