ISTA suddenly "fails to start"

[bamboocha]

Sorry - so long story short:
My Problem is: Ista 4.19 (?) stopped working from one day to another. (Failed to Start ISTA..)
Now i downloaded 4.3XX and used the installer (changed Installation path ec.) but it's the same problem. (also tried 4.5xx )

I'm gonna receive a new HDD today - hope that this will help.