QPC2 is the commercial QL emulator for the PC. There are also a number of other emulators that are shareware and are also very capable. Recently at QL Heaven the local PC was "upgraded" to Windows 7 and new things happened with QPC2. Basically files save to the QXL.win hard disk container were not retained after QPC2 was shut down. This it seems is down to permissions in the latest version of windows. This did not seem to be an issue with XP before. The solution after struggling around a bit was to run QPC2 always as the administrator to allow it to write to the PC's hard drive through the QXL.win filing system.
Incidentally as part of the investigation QPC2 3.34 (vista) was installed but this neither helped or showed any compatibility problems as did the previous version of QPC2 that had been in use of XP.