multiple OS at same time on 1 machine?

Is it possible on a pc to run say 2 OS's at the same time, and i dont mean duel boot. I mean being able to tab between the 2 OS's or something like that. I use to have a mac along time ago and using virtual PC i could switch between windows/mac Os without having to reboot my system. It was slow as hell and buggy but wondering if the same would be possible on a PC.

You've never heard of Virtual Machine? There are a few Windows programs available that will allow you to run a different version of Windows within a virtual session... I'm not sure if it allows Linux or not. I do know that you can install Linux and run Windows in a virtual session...

It is not as straight forward as this. Virtual machine runs some key OS platform components in order to make programs work not the whole OS is run. Appart from dual boot I am afraid that this is not possible. Especially with Linux. XP's NTFS is also too complicated and secure.

I said virtual machine like Zoron but meant virtual PC as above. It runs the OS in a virtual state allowing compatability related issues to be resolved however it is not the full OS just the core components and GUI. It all depends on what you want to do with the 2 OS's when they are running. NTFS will also throw in some spanners. If you had XP on a FAT16 file system compatabillity would be more sucessful but not as secure.

I have 32bit XP and 64bit XP ...When comp. starts it just give me option between to start 32bit or 64bit version, i don't know if you want to have linux and xp on one machine but it is definitely possible.