Is this happening on just one machine, or have you tested on another machine?
Assuming that your installation source is unchanged, the predominant reason for this type of problem is some sort of change to the operating system environment you are using. Perhaps an antivirus update has started reporting false positives for one or more files in the WIS 9 install (this has happened before), and is blocking file access, leading to the hanging problem. The answer here is to run all your antivirus and antispyware solutions on full scan mode and see if you get any reports of positive hits involving any WIS 9 files.
You may also have picked up a virus which is affecting your system,
Hardware issues may be creeping in - check the event logs for any entries recording disk read errors or any other hardware related issues.

If you have access to any virtual machine software such as Virtual PC or VMWare, install a clean edition of your preferred operating systemm and then install WIS9. Leave out any antivirus programs.
Check if this now works OK with your project files.