|Clamraker, start>settings>control panel>regional & languages, take a look at your default language. You can set it as you like.|
BTW, my guess is that as it was changed, a worm/trojan was installed. Not really a big deal, but something that needs to be handled so you don't have future problems. Be aware that a virus and a Trojan are similar, but not the same. Many times, an AV detects one it can't clean, other times, it gets missed entirely.
If you need to clean one, Superantispyware (info only. I’m not paid for recommendation. WARNING! FYI, a full scan on mine takes over an hour.) can do the job and you can get it free @:
among other places. They have a Vista compatible version if needed. Dunno about Windows 7 or later.
If it turns out that you need to use it, be sure to update Superantispyware prior to running and disable 'restore' (restart after cleaning) so the nasty doesn't get put back. They just released a new update recently and it changes all the time. Things are in a constant state of flux.
The restore thing is critical. May not be your deal at all, but won't hurt anything to try.
Ed in Texas.