An IE window opens up with the title Monitor. But it sits in the top corner of my desktop and seems to do nothing. Am I infected?

If you are the only user and this is a recent change and you have NOT added any programs or addons, then you should scan for malware.
Scan with your antivirus and antispyware programs you now have. You could use the two programs in links below.

Install Super Antispyware free. Run it in safe mode. Allow it to quarantine whatever it finds.
http://www.superantispyware.com/

Run the online scan for Bit Defender in normal mode. Allow it to quarantine whatever it finds.
http://www.bitdefender.com/scan8/ie.html