Not sure why. You might need to clear the browser cache.
1. From the Tools menu, select Internet Options... .
2. Choose the General tab.
3. Under Browsing history, click Delete... .
4. Next to "Temporary Internet Files", click Delete files... .
5. Click Close, and then click OK to exit.
You might need to re-install anything that has stopped working.
Disable the System Restore Utility to prevent re-infection from an old one
1) Right click the My Computer icon on the Desktop and click on Properties.
2) Click on the System Restore tab.
3) Put a check mark next to Turn off System Restore on All Drives
4) Click the OK button.
5) You will be prompted to restart the computer. Click the Yes button.
Now re-enable System Restore
To re-enable the System Restore Utility, follow steps one to five and on step three remove the check mark next to 'Turn off System Restore on All Drives'.
1) Right click the My Computer icon on the Desktop and click on Properties.
2) Click on the System Restore tab.
3) Remove the check mark next to Turn off System Restore on All Drives
4) Click the OK button.