Hmm. That should not be the case. Could it be coincidence?
Just a speculation:
After you did a fresh win7 install, the system might be busy updating something and causes CPU going high. And at that moment, you installed youwave and saw the high CPU.
Can you try reinstall YouWave and observe? You may reboot your machine after reinstallation.
i'm happy it was a false alarm .. seems like the system was missing some chipset drivers - it's working as expected

there's one bug i found: when changing the keyboard layout to german, restarting youwave - it works. but after the next reboot it is reset to english again.
thanks!
ps: could you please add support for the google market / connecting to google account for syncing contacts (i'm using whatsapp)