brian123

Yes, you can install 2 os on a hard disk. You install first win-xp. (very importent, because when you install first vista xp-boot maneger cannot boot ) during the install windows will ask you what you want. ( repair, install ) your choice is install, then you can make patition now. Please make 3 or more (4) partition. First one 10 gi. for win-xp (c ), than make a second partition from 20gi or more (better 25 gi. ) for win-vista lately (d). than you make thirth or more partirion (e,f,,,) for yours data. Now you install now yours win-xp on (c),when finish you set yours hardwere drivers. After this you can install yours win-vista on (d).:onion14:

brian123

No, i cannot help you. Because vista boot manager write over the xp bootmanager. so after the both installation you have to start your pc you have the choice by bootmanager xp or vista. When you install your vista first xp bootmanager cannot write over vista bootmanager. you have by start your pc only!!!!! vista.
I have 3 os on one!!!! harddisk too.:onion14: