dual boot-stick drive problem

Hi all, wonder if someone can help. Have XP installed on c:\ and then installed Vista on D:\ (seperate drive). Dual boot working perfectly for months. Suddenly I buy a small USB stick 0.5Mb works perfectly which ever OS I am running. The problem is (there had to be one) if I leave it plugged in XP boots on power up but if I choose Vista on power up, Vista will not load....usual error winload.exe is corrupt or missing which is not the case at all. Unplug the stick, reboot into Vista, plug stick back in ...works perfectly as a temp measure. The question is what do I alter and how do I do it? Gratefully yours....

Hello Terry, welcome to NST

Make sure the USB device in the boot sequence is below the two hard drives you've got in the BIOS. If its still not working do not have the USB drive connected as you boot Vista. The BIOS is considering the USB device another drive in the system and mucking up the boot.
Hello Justin
thanks for the reply. Sorry its took so long to get back. Been on hols. Checked in BIOS c:\(XP) boots first. CDrom boots next followed by floppy last. Stick is not in the boot sequence but I agree with what you said. It boots fine without it. Problem is I start and change OS from another computer over my network so Im not there to pull out stick. Any suggestions?
Thanks Justin, will do though very inconvenient. Do you know why the BIOS is doing this and how can I change it. Once loaded windows is reporting that the stick is F:\ in both operating systems. (C and D hard drives and E cd Rom. If windows can get it right why can't the BIOS?
You could try disabling/enabling BIOS USB support to see if you get different results if your BIOS allows it, but unfortunately since it doesnt show up in the boot menu there's not a lot you can do (even if it did still no guarantees). If you want to keep trying see if the your computer manfacturer has an BIOS update for your model on thier website newer than the version of the BIOS you currently have and flash it if there is.
Have you given the flash-drive and your HDD partitions permanent letter assignments in disk management ?
If you don't assign one, the system will do it for you as it finds them. This will be the next available letter, so it will look as if it's always the same, all other things being equal.
If it's already plugged in and PnP finds the flash before the HDD, it will assign them letters in the order it finds them, which will be different from the order if you boot the system and then plug in the flash.
It's good practice as soon as you install an OS, to give permanent letter assignments to all of your HDD partitions, your CD/DVD drives, and every USB device you're ever likely to plug in.
That way, the device will always be called the same letter whenever it's encountered and no matter what the order of discovery.
Letting the system assign them dynamically will cause the sort of problem you describe.