Windows application Locking

I have a problem with not being able to use open applications in windows XP.  The Applications just stop responding.  I can see the apps in the taskbar but they will not open.  When I check the Task Manager, they show as running.  The CPU usage is not high.  I can open other windows from the desktop, for example, another IE browser and be able to work.  infact, I am using a new browser window right now, the other is frozen at the taskbar.  I run Wn updates regularly.  Thia is happening so often and frustrating.  What could be the cause or what can I do.

I also get the "initializing folders" when I try to save a document for the first time, be it on the desktop or shared drive.  I eventually get to the drive that I want to save to and see the folders, but I cannot open the folder; it acts as if it's frozen.  I will then back out and tey again.  This time it gets me to the folder option rifgt away then I can save.  I have to go throgh this for every new file.

Thanks