I will try to bottom line this quickly and easily. I have an old Dell Inspiron 1525 that needs a new hard drive. Lucky me, I have a new Dell under warranty that died and in their feeble attempt to fix it they sent 2 new 1TB SATA hard drives that I get to keep. Here's the rub - I think the drive they sent has Win 7 64bit on it (I could be wrong because I haven't installed it - it may be blank) but the Inspiron 1525 I want to install it on has Vista. How can I make this work? I have the reinstall and drivers disk and I have the Win 7 product key. I am pulling my hair out because if you ask 10 people you get 20 different replies. Some say it will work fine, just change the drive and load the software. Others say because the motherboard hasn't changed it won't work. Does someone - ANYONE have a straight answer? Let me be clear - I prefer to have Win 7 on the old computer, NOT Vista.