You have to know the serial numbers of HP computers and servers in order to get warranty.

If you run Dell machines, you need the Dell asset tags in order to get warranty.
As it turns out, many times you’ll be no where near your computers but have remote access (hopefully).  So how can you get either the HP Serial Number or the Dell Asset tag remotely?  Read on.
For both cases you need to open a command prompt: many of you should be familiar with this, if not, goto the Start menu and type in ‘CMD’ to bring up the familiar black DOS prompt.
See the below table to obtain the corresponding information on the right:
command information
wmic bios get serialnumber HP: shows Serial Number, Dell: shows Dell Asset tag
wmic csproduct get name HP: shows model name: Dell: shows base model
wmic /namespace:\\root\wmi path MS_SystemInformation HP: shows product number, Dell – nothing man, just nothing
This handy spot of information might come in handy for you one day if your ILO or Dell Open Manage software isn’t installed.