System Health Report — a PowerShell Diagnostic Script

The Goal

I wanted hands-on practice with PowerShell and the CIM/WMI classes that underpin a lot of real Windows administration, so I built a script that gathers the checks a helpdesk tech would normally run by hand — uptime, CPU load, memory usage, disk space, recent system errors, and the processes eating the most resources — and writes them all into one timestamped report.

How It Works

Get-SystemHealthReport.ps1 is organized as a set of small functions, each responsible for one section of the report, called in sequence and captured to a text file with Start-Transcript:

• System Info — hostname, OS version/build, and uptime since last boot, pulled from Win32_OperatingSystem and Win32_ComputerSystem via Get-CimInstance.
• CPU — processor model and current load percentage from Win32_Processor.
• RAM — total, used, and percent-used memory, calculated from TotalVisibleMemorySize and FreePhysicalMemory.
• Disks — capacity and free space per volume, with anything under 15% free flagged with a "LOW SPACE" warning.
• Recent Errors — the last 5 Error/Critical entries from the System event log via Get-WinEvent.
• Top Processes — the top 5 processes by cumulative CPU time and by working-set memory.

The disk-space check was the part I spent the most time on — flagging low space automatically instead of just listing raw numbers felt closer to what an actual monitoring script should do:

function Get-DiskSection {
    $volumes = Get-Volume | Where-Object { $_.DriveLetter }

    foreach ($vol in $volumes) {
        $sizeGB = $vol.Size / 1GB
        $freeGB = $vol.SizeRemaining / 1GB
        $percentFree = ($freeGB / $sizeGB) * 100

        [PSCustomObject]@{
            Drive = $vol.DriveLetter
            SizeGB = [math]::Round($sizeGB, 2)
            FreeGB = [math]::Round($freeGB, 2)
            PercentFree = [math]::Round($percentFree, 1)
            Warning = if ($percentFree -lt 15) { "LOW SPACE" } else { "" }
        }
    }
}

Sample Output

Run against my own laptop, the script produces a report like this (trimmed for length):

===== SYSTEM INFO =====
Hostname  : LAPTOP-HELLA79T
OSVersion : Microsoft Windows 11 Home
Build     : 26200
LastBoot  : 7/15/2026 10:27:42 AM
Uptime    : 0d 0h 4m

===== CPU =====
Model              : Intel(R) Core(TM) i5-1035G1 CPU @ 1.00GHz
UtilizationPercent : 56

===== RAM =====
TotalGB     : 11.75
UsedGB      : 6.98
PercentUsed : 59.4

===== DISKS =====
Drive SizeGB FreeGB PercentFree Warning
----- ------ ------ ----------- -------
    C 929.95 809.76        87.1
    D 929.95 850.72        91.5

===== TOP 5 BY MEMORY =====
Name       Id MemoryMB
----       -- --------
Code    16456   574.69
Code    13096   413.25
MsMpEng  4968    403.7
firefox  9244   374.92
firefox 11572   322.27

What I'd Add Next

• A -ComputerName parameter and CIM sessions to run the report against remote machines instead of just locally.
• Export to HTML or CSV so a report is easier to skim or attach to a ticket.
• Wrap it as a scheduled task to capture recurring health snapshots over time instead of a single point-in-time run.

Skills Demonstrated