Err.... this CD is for HP. Can the installation be executed?

I managed to get WindowsXP pro original OEM CD from my company as my company is no longer using them. But on the CD cover it's written "Includes Service Pack 1a". that's mean it's sp1 right?
If i turn on the automatic updates, will it be updated to sp2?

Thanks in advance 

Yes, it will update. as long as it is legal and original.

But technically OEM license is non transferable and illegal if you want to do what you said earlier. It should only be installed in the PC that the OEM license was purchased with. That's why it is called OEM.

Previously the CPU that uses this CD-key is using Vista Business now. that means now no pc is using the CD-key. If i install this OS to my pc, will microsoft detect it as genuine windows?

This is bad

What will happen if i install it into more than 2 CPU? 

Sorry that i ask too many question cos all this time i'm using jack sparrow edition software and i'm not exposed to genuine software >_<