Code:
#pragma endregion
private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) {
int start_cyl = Int32::Parse(textBox1->Text, NumberStyles::HexNumber);
int end_cyl = Int32::Parse(textBox2->Text, NumberStyles::HexNumber);
int start_head = System::Int32::Parse(textBox4->Text, NumberStyles::HexNumber);
int end_head = System::Int32::Parse(textBox5->Text, NumberStyles::HexNumber);
int ans = (start_cyl * 0x80 * 0xf) + (start_head * 0x80);
int ans1 = (end_cyl * 0x80 * 0xf) + (end_head * 0x80);
textBox6->Text = ans.ToString();
textBox3->Text = ans1.ToString();
This did the trick!