How and when should connect data cable to android tablet devices for flashing?

I have an android tablet "Eurostar epad giene" and it is pattern locked and i forgot pattern, So i need to factory reset my tablet, But I cannot access recovery menu by pressing volume up button and power button together. When press both button it is entering to FASTBOOT mode.So am planning to flash my tab. So downloaded firmware from official site of eurostar. and it contain drivers(MTK vcom USB Driver),flash tool(SP Flash Tool),and firmware. And i have open the application and also installed drivers. But my tab is not detecting on this software. so pls help me to connect my tab to pc. Tel me is there any method to connect the cable to tab.