Installing Windows XP in Windows Vista PC

We have been discussing about this afternoon about my husband's HP dv6626 computer that don't have Operating System. Originally, the laptop had a Windows Vista program but was removed in the laptop. My hubby want to put there now a Windows XP program because he don't like Vista. He heard a lot of people complaining about this program. As he inserted an XP CD to install the program, there is a message that says, "no Operating system is found". He tried it a lot of times but still the same problem. Anybody who is a computer genius out there who want to help..appreciate it in advance..Have a nice weekend to all!

I Need To Upgrade The OS of My PC

It has been some months that I am planning to upgrade the Operating System or OS of my pc. It has a Windows XP with SP2 operating system. The SP3 is still waiting to be upgraded. I am just scared to lost some important files, data or documents in my pc one I will upgrade it to SP3. I will wait until my new notebook will come next week so that I can change the OS to SP3. I just want to make it sure before I do it. I have been planning to do it couple of months ago but life online and offline is always busy! more updates to come later!