For now you can try the following.
Since your Hd doesn't seem to be running low on space, I want to make sure we can get rid of the Virtual memory problem. Please follow the next steps:
Go to Start and then Right click on My Computer
Click on Properties and then click on the Advanced Tab
In the Performance area click on the Settings button
When the new Window opens click on the Advanced Tab
In the Virtual Memory area please click on Change
Half way down the window you will see the System Managed Size option
Select this if it isn't already selected
Now click OK, OK, OK. This will now hopefully end the warnings.
Let me know how everything works then.