Let me restate this problem
Hard drive failed on my Acer Aspire 5734z. I replaced it with a new WD hard drive. Apparently, I incorrectly thought that I could just reload windows 7 Home Premium 64bit from any source, and use the product activation key on the bottom of the PC to validate it. It never asked me for an activation key when I installed it, and, I tried to go into system properties and enter it there. There was no place to enter the key. I also tried to search for slui.exe to see if I could enter it there. But I got:
C:\Windows\system32\slui.exe
Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item.
I am the only user and the administrator on this PC. I feel like I must have done it wrong from the get go.
Can someone tell me, from square one, how I should ( or should have) proceed(ed) in order to get a validated Windows 7 Home Premium 64bit OS installed without having to repurchase it? Everything was working great until I tried to download Microsoft Security Essentials. That's when it said this copy of Windows was not valid (or however they put it) saying that Security Essentials could only be installed on a computer with Genuine Windows 7. Everything else works fine, but I would like to validate Windows and be able to use MS Security Essentials.