Having different OS's on two hard drives

[Martok]

So one of our fellow Grogs has generously given me his "old" PC, as it's still almost an order of magnitude better than my current machine (which is even older).  My intent is to pull the hard drive from my old computer and install it alongside its counterpart in the new one. 

The caveat is that the new PC has Windows 7 on it, whereas I have XP installed on my old one.  Since some of my older games are known to not run very well on 7 (or at all), I want to at least keep XP on my old hard drive, and possibly install XP on the new hard drive as well.  However, this brings up a number of questions: 


1.)  Which is better -- having XP on one hard drive and 7 on the other?  Or just have XP on both? 

2.)  If the former, how do I install XP on the new hard drive? 

3.)  If the latter, how do I set things up so that I can access the old hard drive (with XP)?  Or is it going to be too much of a pain in the ass to set things up this way? 


Advice & input is greatly appreciated! 

[Arctic Blast]

My first move would be to install the games you think you might have trouble with on the Win 7 machine and find out. Might save yourself a lot of time and work, since the number that won't work is actually quite small.

[MIGMaster]

^ Probably the best route to go - different OS'es on different dives can create a big frickin' mess if you don't have a front-end utility like System Commander - its called Partition Commander now - not quite as cool !

https://www.vcom.com/partition-commander

[eyebiter]

Are these IDE or SATA hard drives?. One solution is a removable hard drive.  You would power off PC, install boot hard drive of choice, then power up computer.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817993031

[junk2drive]

Which version of 7 is it? If pro or ultimate you may have a compatibility layer with XP already on it.