I bought a new drive and Vista Ultimate and wanted to have both xp pro and vista on dual boot for this one drive. I partitioned it right down the middle 115GB each (approx). I installed XP Pro without a hitch and then ran Vista within XP to install on the other partition. Once vista was booting up for the first time, everything seemed to be running fine. But after it had been on for a few minutes everything started to go a little strange. Everytime that I tried to open a program/folder I got a 65535 error. I looked it up and it seems to be a read error of some sort. I reformated the one partition and tried again and same thing. When I reboot and choose vista at the boot menu, it runs check disk (or whatever it's called now) and get a whole bunch of errors that it tries to fix. After that finishes, it's unable to launch vista again, even in safe mode. I then did a low level format on the whole drive and reinstalled XP. It's running fine (XP Pro SP2) and I'm going to reinstall vista but I'm expecting the same problem to happen again. Anyone have a clue what might be going on? Thanks in advance for any insight.