I have an velleman K8055 and when i put it in my pc (windows 7) the Power LED is ON, LD8 lights on, then off and stays on. So i tried it on an other pc (vista) and everything works perfect.

I also looked at USBview.exe and the kit device buss speed was Full

The kit works perfect but there is something with the USB driver on windows 7. How can i make it work?

You may have to “reset” the USB driver.
Please see this thread for possible solution: viewtopic.php?f=3&t=6564

Sadly i keep getting error “USB device not recognized”.

The kit “speaks” in USB 1.1 right?

What if i buy an USB1.1 hub and connect it to the velleman kit, would that work?

Yes, the K8055 “speaks” in USB 1.1.
Anyhow it should work with USB 2.0 ports without any problems.

Can’t say if there is any help to use a USB1.1 HUB.