You realise Compaq is HP, right?
No,no, no and no.
Ahem, sorry about the mini-rant....
Compaq is a business division of HP as the result of a merger between Compaq and HP. But that's about all it shares with HP.
Everyone knows, if you want HP quality, you buy a box with an HP badge on it (addmittedly there are some questionable HP products, particularly in their printer range and some of their cheap servers..... but their core IT kit is generally quite good.... never had an issue with any of their desktops, for example).
Compaq is only really there to cater for the price sensitive consumer market. Hence the difference in build quality and the reason why HP use the Compaq brand name on the kit, as a differentiator.
In IT, you get what you pay for.