Added make/model & serial # commands

ps-commands.md

@@ -51,3 +51,17 @@ Get-ADPrincipalGroupMembership (Get-ADUser $Username) | select-object name
 ```
 
 <br>
+
+### Fetch $ComputerName's Make & Model
+
+```powershell
+Get-CimInstance -ComputerName $ComputerName -ClassName Win32_ComputerSystem | Select-Object -Property Manufacturer, Model
+```
+
+<br>
+
+### Fetch $ComputerName's Serial Number 
+
+```powershell
+Get-CimInstance -ComputerName $ComputerName -ClassName Win32_bios | Select-Object -Property SerialNumber
+```