Yes, you can... but... the disk has an internal code that does not match the product ID on the sticker... be sure to look for a way to use your own product ID.
There are some rules.
The friend's Dell Windows disk must be the same series as yours... If his is Service Pack 2, yours must be Service Pack 2.... and so on, because the product ID only works on a limited number...
Look at your Windows XP lable and compare it to the one on your friend's machine.
But you can call Dell, and if the machine ownership is registered to you, Dell will usually help you get a replacement disk... and it will be Service Pack 2. If you find the Dell rep to be unhelpful, call back again and again until you get one with the correct training.