I do not normally advertise other companies.

However merit is due.

This Secunia PSI is a free kit able to scan your PC and detect outdated software

it scans software on your system and identifies programs in need of security updates to safeguard your PC against intrusions on your machine. It then supplies your computer with the necessary software security updates to keep it safe. The Secunia PSI even automates the updates for your insecure programs, making it a lot easier for you to maintain a secure PC.

Using a scanner like Secunia PSI 3.0 is complementary to antivirus software, and as a free computer security program, is essential for every home computer.

http://secunia.com/vulnerability_scanning/personal/