1) Download and install the microsoft application compatiblity toolkit. You can easily find that in Microsoft's site in download section. I think the last version of it is 5,5.
2) Start the 'Compatibility Administrator' with administrator rights. If your UAC is off, no need to adm. rights by the way.
3) Click the 'New' Button
4) Right click the new database. Select 'Create new application fix…'
5) Name your program and vendor however you like. Browse to your por2main.exe file.
6) Select 'None' for operating system modes. Click Next. Tick the 'ForceDirectDrawEmulation' compatibility fix. (No need to select additional compatibility modes)
7) Click next and finish.
8) Save your database.
9) Right click the database and select install. This will install the database.
10) Close the compatibility administrator and start POR2. That's it. Play & Enjoy.
To do that once is enough to solve the issue. No need to do that everytime you want to play POR2.