...if your phone working, I suggest to don't make fullflash, only firmware upgrade. Use file "A75_340300_service.zip" from http://eh.student.utwente.nl/~landy/index.php?dir=A75/
user: mobile
password: elibom
or go to http://www.honzahavana.com/flashessiemens.htm and download "A75410300.zip" (you see Siemens A75).
If your phone is damaged (make bzzz and/or splash display) go to http://samer4zen.free.fr/abigore/siemens/jokerflashes/ and download "A75_8Mb_010C_FF.rar" (include English, German, Spanish, French, Italian, Russian language pack). Flash using Joker software and check option "ReCalc Keys". After you need to make the firmware upgrade using SWUP file "A75_340300_service.exe".
Maybe announce me if you need to make fullflash in your phone and will prepair the fullflash file for polish language.
dagos