Run this basic security check in case this is some form of malware problem:
Is your
Anti-virus program current and
updated? If not you can download a free anti-virus program here (US Link):
AVG FreeWhen you have downloaded and installed it you need to go online to register it and update it. (It will probably prompt you to do this.)
Once you have installed AVG uninstall your old Anti-Virus software because you should only have one running on your system.
Do you have any
anti-spyware installed? If not download and update
all of the following:
Reboot your computer in Safe Mode and run the anti-virus scan and anti-spyware scans there.
If you are not sure how to boot in Safe Mode there is a tutorial here:
Safe ModeSee if that helps