File Transfer from old pc to new

I am trying to write a powershell script to transfer files from a users old desktop to their new. I will be running this script from their new computer as the user will still be using their old one while this script is working. My goal is to have the script run and figure out which OS the old computer is running to be able to pull from the write folders and files. All the new computers will be running windows 8, however some of the old desktops are still running windows XP.

Also what would be the correct way of having the script prompt for the name of the "OldPC" and insert it into the script where needed be?

Here is my current script, I know nothing about scripting so any advice or tips would be great.

Thank you very much.

Write-Host "Name of Computer Transfering data FROM"

$userinput = Read-Host "Enter input here:"

$a = Test-Path \\$userinput\c$\documents and settings


If ($a = true)
Write-Host "XP"


If ($a = false)
Write-Host "7/8"



$UserName = [Environment]::UserName
$ComputerName = gc env:computername


If($a -eq $true) {

#WINDOWS XP MACHINE


Copy-Item \\$userinput\c$\documents and Settings\$UserName\documents\* -recurse \\ComputerName\users\$UserName\documents\
Copy-Item \\$userinput\c$\documents and Settings\$UserName\pictures\* -recurs \\ComputerName\users\$UserName\pictures\
Copy-Item \\$userinput\c$\documents and Settings\$UserName\music\* -recurse \\ComputerName\users\$UserName\music\
Copy-Item \\$userinput\c$\documents and Settings\$UserName\videos\* -recurse \\ComputerName\users\$UserName\music\
Copy-Item \\$userinput\c$\documents and Settings\$UserName\desktop\* -recurse \\ComputerName\users\$UserName\desktop\
Copy-Item \\$userinput\c$\documents and Settings\$UserName\favorites\* -recurse \\ComputerName\users\$UserName\favorites\
Copy-Item \\$userinput\c$\documents and Settings\$UserName\AppData\Roaming\Microsoft\Signatures\* -recurse \\ComputerName\users\$UserName\AppData\Roaming\Microsoft\Signatures
Copy-Item \\$userinput\c$\documents and Settings\$UserName\AppData\Roaming\Microsoft\Outlook\*.n2k \\ComputerName\Users\$UserName\AppData\Roaming\Microsoft\Outlook\
} else {

#WINDOWS 7 OR 8 MACHINES

Copy-Item \\$userinput\c$\users\$UserName\documents\* -recurse \\ComputerName\users\$UserName\documents\
Copy-Item \\$userinput\c$\users\$UserName\pictures\* -recurs \\ComputerName\users\$UserName\pictures\
Copy-Item \\$userinput\c$\users\$UserName\music\* -recurse \\ComputerName\users\$UserName\music\
Copy-Item \\$userinput\c$\users\$UserName\videos\* -recurse \\ComputerName\users\$UserName\music\
Copy-Item \\$userinput\c$\users\$UserName\desktop\* -recurse \\ComputerName\users\$UserName\desktop\
Copy-Item \\$userinput\c$\users\$UserName\favorites\* -recurse \\ComputerName\users\$UserName\favorites\
Copy-Item \\$userinput\c$\users\$UserName\AppData\Roaming\Microsoft\Signatures \\ComputerName\users\$UserName\AppData\Roaming\Microsoft\Signatures
Copy-Item \\$userinput\c$\Users\$UserName\AppData\Roaming\Microsoft\Outlook\*.n2k \\ComputerName\Users\$UserName\AppData\Roaming\Microsoft\Outlook\

}