How do I dual boot my computer to run Windows XP and Vista?

Question To begin with, I am not totally literate when it comes to knowing what goes on "inside." I would like to know if it is possible to partition two different operating systems on the same computer. I am using Windows XP, but I would like to try Vista. I have heard good and bad things about it, so I'm reluctant to dispose of XP unless I'm convinced that I really like it. Can you please give me some detailed directions as to how I can accomplish this? Thank you.

Answer
it's not only possible but it is done VERY often. But you may need to get some help in actually doing it.

What you want is called "dual boot" (or, for more than two OS', "multi-boot"). As long as you are doing no more than two OS, you can do it with just the OS' (e.g. software on the OS CDs), providing that you can repartition your hard drive into [at least] two partitions; while you can have two OS' on the same hard drive, they generally have to be in separate partitions. If the hard drive is currently fully used (fully partitioned), you may have to do some repartitioning first, so you may need "Partition Magic" or a similar partitioning software. Then you can go after setting up dual boot. The general process is to install the older OS first, then install the newer OS in a separate, blank partition (so you might have XP in C: and Vista in D:).

However, with XP and Vista, there is nasty catch: Due to a conflict between how XP and Vista work, if either Operating System sees the partion containing the other, there will be some corruption of the "other" OS. The most serious consequence of this is that the System Restore function will be lost for both OS', and there may be some other , less serious consequences. The choices basically are to live with this, or to arrange to "hide" the partition containing whichever OS you did not boot into (whenever you reboot you will be given a menu of the two OS' and the chance to select which one to boot up from). If you choose the "hide" approach (probably best), you will need a 3rd party "boot manager" since the Microsoft boot manager doesn't implement this function. If you do a web search for "dual boot" or "boot manager", or similar, you will get a lot of hits that should help you to both select a boot manager (some are free, some are not) and give you instructions for setting things up.

What I usually recommend for people setting up dual boot is this:

-Oldest OS on C:
-Newer OS on D:
-All data for both OS' (including "My Documents") on E:

Setting this up takes some effort to get all the programs installed under either or both OS' to store their data on E: (including making a "My Documents" folder on E: and having both OS' recognize it as THE "My Documents" folder), but it gives you the flexibility to use either OS and see the same data. System Restore won't work on E: if you do this (since both OS' will, by definition, see that partition), but system restore doesn't deal with DATA anyway, it only deals with system files such as drivers and the registry, which won't be on that 3rd data partition.

As to specific instructions, again, that can get pretty lengthy, and the best advice I can give you is to do a web search. There are plenty of sites that do have step-by-step instructions, but the length of the instructions makes it kind of prohibitive to actually put them directly into this post.