Posted 12 August 2009 - 05:11 PM
We'll let the experts add to what I say, but if you want both operating systems and to choose which one boots when you power up, yes you can do that. The hard drive will have to be divided into another partition where you will install XP, and it will be like it's on its own drive.
For Vista to work well, you'll need at least:
1 GHz 32-bit (x86) or 64-bit (x64) processor
1 GB of system memory
40 GB hard drive with at least 15 GB of available space
It will not run well with the bare minimum 1GB of RAM memory, though. 2 or even 3 is much better. Most new hard drives have plenty of room to divide it into partitions, but 40 and 15GB free disk space is pretty cramped. It would boot and run but you wouldn't have much room to store aplications and data.
XP runs flaelessly with 1GB of RAM and takes only 1.5GB free space on the drive, but like Vista, you need more room on the drive to actually use it.
RAM memory = speed. HD space makes little difference in how fast a computer runs unless you have a really cluttered or crummy drive.
As long as you have a comfortable amount of disk space to put them, your updates will not be an issue.