I have a PRS alpha running on a windows 7 HP tower. I have been running the machine daily for years but lately I have been experiencing a problem with more and more frequency. The program will stop on a random line of code, the spindle continues to run. The cursor is no longer trapped in the STOP field and the only way to stop the spindle is to quit the program. (space bar and other keys do nothing).

Any suggestions on what gremlin has crept into my system?