Short answer: You can't. If your windows system is dead, you'll need to restore to another windows system. From there you must migrate your database using Oracle utilities:
Metalink indicates the following:
There is no Migration utility (Script or DBUA) to perform a cross platform migration.
To change platforms require the database instance be re-built and / or the data moved using one of the following methods:
- Export / Import to include the use of Datapump facilities. all versions support Export/Import but for Datapump 10.1.0.2 or higher is required
- Transportable Tablespaces 10G or Later
- RMAN Convert Database functions. 10G or Later
The choices available will depend on BOTH the OS and Oracle versions of both the source and destination.
For example RMAN Convert Database only works if both source and destination belong to same ENDIAN format.
Transportable Tablespaces has a convert function to convert from one ENDIAN format to another.