Install windows 8 without installation key

To skip installation key request you need to put file ei.cfg into instalation DVD/USB /sources folder:

[EditionID] 
Professional 
[Channel] 
Retail 
[VL] 
0

If you leave [EditionID] parameter blank - during installation process you will be able to choose which versionto install.

Clear windows 8 startup in registry editor.

Run Regedit

HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows
Clear any value in key Load

Find out old AC Computers

PowerShell script:

# Gets time stamps for all computers in the domain that have NOT logged in since after specified date

$time = Read-host "Enter a date in format mm/dd/yyyy"
$time = get-date ($time)
$date = get-date ($time) -UFormat %d.%m.%y

# Get all AD computers with lastLogonTimestamp less than our time
Get-ADComputer -Filter {LastLogonTimeStamp -lt $time} -Properties LastLogonTimeStamp |

# Output hostname and lastLogonTimestamp into CSV
select-object Name,@{Name="Stamp"; Expression={[DateTime]::FromFileTime($_.lastLogonTimestamp)}} | export-csv old_users.csv -notypeinformation

Source: http://blog.mattvogt.net/

When VLOOKUP is not working because of numbers stored as text

If you want to store data with leading zero (Format cell-> Special) - you will have problems with LOOKUP formulas because of "The number in this cell is formatted as text or preceded by an apostrophe". The simplest solution is to multiply search range with 1.

Example:
=VLOOKUP($A$2:$A$718*1;Sheet2!$A$3:$B$725;2;FALSE)