The following command is built-in to Windows:
systeminfo
It doesn't give much, but it does address your request for processor, memory, and network.
Disks can be easily queried for all sorts of info from the following built-in Windows command:
fsutil
You'll want to try fsutil that with a /? switch to see some of the options available. More specific drive information is available within diskpart, also a built-in command.
For "speed", I'm not sure exactly what you mean. Perhaps you're looking for a benchmark utility? If so, try SiSoft Sandra. The free version is available here (Go to download & buy at the top).