Root folder database install issue

Hi guys,

I'm running Windows 7 Ultimate.
Installed nopCommerce from MS WPI, went swimmingly when installed into Default Website/nopCommerce.
Installed nopCommerce again, into New Website/
Following the wizard through, I get to Database creation where it throws this:

An error occured[sic] when creating database: The file "c:\Program Files\Microsoft SQL Server\MSSQL10.SQLEXPRESS\MSSQL\DATA\someshop.mdf" is compressed but does not reside in a read-only database or filegroup. The file must be decompressed.

I look in the folder, and there is no such file.
I get the same error using the sa account or using integrated authentication (with the account having SysAdmin rights). It also doesn't make any difference whether I perform this operation remotely or locally.
I did not choose to install sample data.
The SQL Server instance is SQL Express (and therefore SQL Server Name is MY-PC\SQLEXPRESS)

(Additionally, it doesn't make any difference if I ask it to create sample data.)

Solved - due to the volume of infrequently used text files in the Program Files\SQL Server folder, I had the Compression attribute set to True. I'd forgotten about the attribute and for some reason, Windows Explorer wasn't showing the files in blue. Turning off Compression fixed everything. Now I'll have to be more selective about which folders I compress :)