SQL Server 2008 RTM and Download Manager Problems

I have downloaded SQL Server 2008 RTM couple of times from this site but each time I am asked to provide a product key. Where can I find this key?

I posed this question to several forums as I faced with this problem repeatedly.Here are the details and more importantly, the answer I found.

I started at this site:

http://www.microsoft.com/sqlserver/2008/en/us/trial-software.aspx

I down loaded from this section:

Download SQL Server 2008 Enterprise 180-day Evaluation

Download it now.--> button

This takes you to this link [Evaluate Microsoft SQL Server 2008 today]:

http://technet.microsoft.com/en-us/bb851664.aspx

Drop-down selection: Select Your Language(Country)

Choose English(United States)
Hit on the > button

Start downloading. Takes about an hour or so on cable:

Since Launch after download was selected the launch starts and I get the following message:
Key Expired

If I tried to open the SQLFULL_ENU.iso file or try to copy it to a DVD I get the following error:

Finally the work around:
Forget about the procedure [Copy it to a DVD and open the DVD to get to the setup.exe file.] suggested.

I downloaded the WinRar. It is indeed a powerful program and you can directly open the SQLFULL_ENU.iso file. It does take around 10 mts to open the archive, but no problem. It immediately shows all the files. It can unpack not only ISO but many other formats. On top of it, no need to burn a DVD and worry about non-compatible DVD drives(notorious in their own way).
Here is the fully open SQLFULL_ENU.iso file.

Bye bye to Download Manager's Launch routine. Welcome to WinRar.