A month ago, my Vista had a boot up error. My cousin couldn't find the problem so he hooked me up with Mandriva (a Linux OS). He took it back and installed Vista on a USB and split the harddrive with Vista and Linux. At first Vista was fast, but not it can be really slow and glitchy. Especially when I watch a video on the YouTube or something. It lags the whole time even when I let the whole bar load. I'm not running a bunch of programs, and I set the priority to realtime every time I start Firefox. Any help please?