In addition to Matt's suggestions, if you've installed any additional toolbars to IE...i.e. the Genieknows.com toolbar, then I would suggest uninstalling it. Some of these add-on toolbars, especially like the one I mentioned, are notorious for hogging system resources. Also, you didn't mention if you've run a virus scan since the problems started...if not, then I would strongly suggest it.
I would also suggest running Event Viewer (in order to access the error logs, and check for any critical errors)...Start | Run | Type
eventvwr.msc and hit OK | Highlight "Application" and "System" independently in the LH pane | Right click the error message(s) (critical errors are in
Red), and select "Properties" | Write down a couple of the error messages
exactly as they appear (under the "Description" field), and post them in this thread.
Also, open the System Information tool by typing
msinfo32 in the Run box | Expand "Components" | Highlight "Problem Devices", and look for any problems that might be listed there.
In addition to using Ad-Aware, I would also suggest running SpyBot Search & Destroy, which you can download here...
http://www.safer-networking.org/...and Hijack This, which can be downloaded from MajorGeeks here...
http://www.majorgeeks.com/download3155.html
Also, the following site may be of some additional help to you...
Dealing with Unwanted Spyware and Parasites