How do you install two different OS in a computer?

Two Operating system can be installed in your PC but it depends on what OS you want to install and in which order

supoose take an example of Windows OS

Win95----> Win98-->Win2000/millennium/NT--->Winsow Xp----> Win Vista

Linux

For diffrent OS

Wrong is Linux then window

Correct window then Linux

this is because of file systems difference in each..

Both support diffrent file system and as theOS uprade its file system also upgrades

In the Macintosh Operating system, you have two or more different system folders, and using the Startup Disk/Folder control panel, you select which operating system you wish to use when you restart your computer. This can include Windows emulators that are installed on the Mac.

First of all, whoever wrote the above answer was somewhat lacking in the use of the English language, or their brain was working faster than they could write/type! Totally unclear what is meant! ->"For diffrent (correct: different) OS ... Wrong is Linux then window ... Correct window then Linux" <-

Now, what is that supposed to mean?

Basically, you should use a Windows OS as the PRIMARY OS in the first active partition, with an average size of between 10GB and max. 25GB (allowing for additional programs, updates and the like). For the next OS, you can use either Linux or a Linux-based OS, on a separate partition (also active). This partition doesn't have to be as big as the Windows OS, because it's not as bloated as Windows. 8GB to 15-20GB is more than adequate. More than 2 OS, is rather unneccessary, and in the long run, could cause more problems.

: When you install win xp in c: then. again boot through CD. and select instalation drive C: again. then show massage. alreadyu installed. then change Windows folder name. after that same procedure.