My mouse seems to be automatically right-clicking every few seconds, and sometimes constantly. My cursor will abruptly become an hourglass for a moment every once in a while, as well. It happens in spurts, as in it hasn't happened for about 10 minutes, but the preceding 20 before that it was happening constantly.

I suspect that my machine is infected with malware of some sort, so I've tried installing Microsoft Security Essentials, but it presents the following error upon installation failure:

My questions are:

• How can I solve the MSE installation issue and run a scan?
• Are there any indications that malware isn't actually my issue?
• Is MSE my best way to go about solving my issue, assuming that malware actually is the problem?

Many thanks!