You should probably boot into safe-mode and delete it from there. Otherwise delete it from command prompt or an external device. Press the F8 key while booting your computer to get into safe-mode.
PC: AMD Phenom 9950 2.6ghz Quad Core, ATI Radeon HD 5770, 8gb DDR2 RAM
Phone: Apple iPhone 5s 64gb (jailbroken)
Handheld Games: Nintendo 3DS XL, Tapwave Zodiac 2, GamePark Holdings GP2X F100