Can I install older version of Windows over Windows XP?

[Ocean's one]

My laptop runs Windows XP, and I've bought some (old) games that won't run on windows XP. Fixes to the system didn't work. A lot of the support sites suggest that I install an older version of Windows. I have a Windows 95 CD, but it tells me to install from DOS. Thing is, Windows XP doesn't have DOS, does it? How can I install them both side by side without buying some multiboot software ? I have both versions, legally, surely can I install them together?

[Ocean's one]

If you want to run older DOS games under XP
Try DosBox.
Link the below.
Also install the D-Fend frontend
That should do the trick, it works for me.
Don't even consider installing an older version of Windows, they're very insecure compared to XP.