Could it be that you do not have enough virtual memory? May be some programs are eating up memory.
If that's the case, you can use the Task Manager to check which processes are using up a lot of
memory and terminate them. I would consider consider which applications needs to start up with
Windows and running all the time, and only keep the necessary ones enabled, and see if it helps. You
can use a program by Microsoft called Autoruns for this. First result if you search with Google.
