Q: How do I check if I have any RAM Slots available and if so, how much capacity is capable of?

Please use the PowerShell Script from the below link:

MemoryCheck Script
password is getac

Or copy and paste the below text into Powershell if you're restricted from using scripts:

Cls
$PysicalMemory = Get-WmiObject -class "win32_physicalmemory" -namespace "root\CIMV2"
$MaxMemoryCapacity = Get-WmiObject -Class "win32_PhysicalMemoryArray" -namespace "root\CIMV2"

Write-Host "Memore Modules:" -ForegroundColor Green
$PysicalMemory | Format-Table Tag,BankLabel,@{n="Capacity(GB)";e={$_.Capacity/1GB}},Manufacturer,PartNumber,Speed -AutoSize

Write-Host "Total Memory:" -ForegroundColor Green
Write-Host "$((($PysicalMemory).Capacity | Measure-Object -Sum).Sum/1GB)GB"

Write-Host "`nTotal Memory Capacity:" -ForegroundColor Green
Write-Host "$((($MaxMemoryCapacity).MaxCapacity * 1KB)/1GB)GB"

$TotalSlots = ((Get-WmiObject -Class "win32_PhysicalMemoryArray" -namespace "root\CIMV2").MemoryDevices | Measure-Object -Sum).Sum
Write-Host "`nTotal Memory Slots:" -ForegroundColor Green
Write-Host $TotalSlots

$UsedSlots = (($PysicalMemory) | Measure-Object).Count
Write-Host "`nUsed Memory Slots:" -ForegroundColor Green
Write-Host $UsedSlots

$AvailableSlots = ($objslot.memorydevices-((($colRam) | Measure-Object).count))
Write-Host "`nAvailable Memory Slots:" -ForegroundColor Green
Write-Host $AvailableSlots