1. Click the 'Start' menu, and select 'All Programs.' Click to launch 'Windows Update.'
2. Click the 'Check for updates' link in the left pane. Follow on-screen prompts to install the updates.

3. Click the 'Start' menu, and select 'Run....' For Windows 7, type 'Run' (minus quotes) in the search bar, and press 'Enter.'
4. Type 'MRT' (minus quotes), and press 'Enter.' This will launch 'Malicious Software Removal Tool.' It is a built-in utility that checks your computer for malware and infections and fixes them automatically.
5. Click 'Next' when you see the Welcome screen.
6. Choose the 'Full Scan' option. Click 'Next' to proceed.
7. Follow on-screen guided prompts to finish the scan and remove errors. Click 'Finish' when done.