CCleaner won't install on my Windows7

I am running Windows 7, latest service packs according to my computer and registry setting, yet when I try to install CCleaner, it tells me that I need to upgrade my operating system to XP or higher. What is CCleaner looking at when it makes this determination? How can I change it? Thanks.

Make sure you downloaded ccleaner from http://ccleaner.com/download.

Make sure compatibility mode isn't turned on for the installer.

Try the slim build from http://www.piriform.com/ccleaner/builds

Or,alternatively, you can unzip the portable build on top of your old install (afterward be sure to delete portable.dat from the folder, if it exists)

I am also experiencing problems upgrading to v4.18.4844 with my Windows 7 Pro machine. I have a notebook running 8.1 and two other DELL PCs running XP Pro, all three of these machines installed & run the latest version of CCleaner with the Active Monitoring with no issues. When I try to update to the latest version with my DELL Dimension E520 running 7 Pro the installer hangs up at installing the .exe file every time. I've had no issues updating with 7 Pro until this version.

UPDATE: Please disregard my last post. I went to the download link you posted, Nergal, and it installed just fine. For some reason the link my old (last) version of CCleaner was sending me to update didn't work, yours did. Thank You.