Can't Refresh Browser Windows

All of a sudden, I can't force a refresh in ANY browser - firefox, IE or AOL, so I can't see changes I'm making on a site immediately. I don't think I did any changes to my browser preferences, and I don't think I had an upgrade to anything before this happened.

I've dumped the Cache and history files, and nadda.

Anyone have an idea on what to do, this is frustrating as hell and making site modifications a total pain.

You know, this is happening to me on IE7 every now and again too, i find myself having to either close the browser and wait 10-15 minutes and re-open it or having to reboot my laptop.

Im wondering if it is something to do with one of the recent M$ updates?

Regards,

Lee