Dell on win 7 not booting + data recovery

Hi Everyone, I have a rather old Dell Inspiron 1525. It's Toshiba 160gb hard drive died 9 months ago unexpectedly and suddenly running win 7 professional with 4gb of RAM. Fortunately I had all the data on an external drive. So I bought a 2.5inch WD scorpio blue 500GB 5400rpm SATA and reinstalled the win 7 professional using an external DVD reader-writer (Freecom) with no problems. I had no...