Question about adding to output with PowerShell

Hello. I created a PowerShell script that searches the event viewer for Service Pack information in the event viewer. It reads from a text file and outputs what it finds. I am still learning my way around PowerShell. I want to add the name of each computer before it searches the next to my output.

For example, the output currently looks like the below.

Error Microsoft-Windows-Service Pack Installer          8 Service Pack installation failed with error code 0x800f0828.                      
           Error Microsoft-Windows-Service Pack Installer          5 There is not enough free disk space to install the Service Pack. Required=4623 MB.
     Information Microsoft-Windows-Service Pack Installer          1 Service Pack 1 installation started.                                              
           Error Microsoft-Windows-Service Pack Installer          8 Service Pack installation failed with error code 0x800f0828.                      
     Information Microsoft-Windows-Service Pack Installer          9 Service Pack 1 installation succeeded.                                            
     Information Microsoft-Windows-Service Pack Installer          1 Service Pack 1 installation started.                                              
     Information Microsoft-Windows-Service Pack Installer          1 Service Pack 1 installation started.                                              
     Information Microsoft-Windows-Service Pack Installer          1 Service Pack 1 installation started.                                              

I would like it to look like the below. I assume I could do something with $Computer but I am not sure how to do so.

Computer 1
           Error Microsoft-Windows-Service Pack Installer          8 Service Pack installation failed with error code 0x800f0828.                      
           Error Microsoft-Windows-Service Pack Installer          5 There is not enough free disk space to install the Service Pack. Required=4623 MB.
     Information Microsoft-Windows-Service Pack Installer          1 Service Pack 1 installation started.                                              
           Error Microsoft-Windows-Service Pack Installer          8 Service Pack installation failed with error code 0x800f0828.                      

Computer 2
     Information Microsoft-Windows-Service Pack Installer          9 Service Pack 1 installation succeeded.                                            
     Information Microsoft-Windows-Service Pack Installer          1 Service Pack 1 installation started.                                              
     Information Microsoft-Windows-Service Pack Installer          1 Service Pack 1 installation started.                                              
     Information Microsoft-Windows-Service Pack Installer          1 Service Pack 1 installation started.                                              

I know it is something simple that I am missing but I cannot see to find it. Any help is appreciated.

$Computer = Get-Content c:\temp\machines.txt
If (Test-Connection -comp $computer -count 1 -quiet) {
  "Searching Event Viewer"
   Get-EventLog System -ComputerName $Computer -Newest 4 -Source '*Service Pack*' | Format-Table Time, EntryType, Source, InstanceID, Message -AutoSize | Out-File C:\temp\ServicePack.log
  }
Else {
  "Machine is offline."
   Exit
  }