I bought a compatible battery for a Sony VGN-CR42S laptop but it would not charge. After a little trial and error I found it was down to a Sony application called ISBMGR.exe. This is located in the Sony programs folder. Rename this, restart the computer and hopefully your compatible battery will be charging properly 🙂
On a 32-bit machine the file is in C:\Program Files\sony\isb utility\
If you are on a 64-bit pc then the file is in
C:\Program Files (x86)\sony\isb utility\