I was wondering if a normal colonoscopy is painful and is a virtual colonoscopy as accurate as a normal colonoscopy and can it detect any cancer?

No: Colonoscopy is not painful. The doctors give you medications to help you relax/fall asleep for the procedure. Virtual colonoscopy is new and as such is not as good as the real thing yet.

Not painful: No colonoscopy is a painless procedure(it is done under sedation, so you would not feel anything). Virtual colonoscopy is still not a well established procedure although it does come 90 close to standard colonoscopy in its accuracy and reliability.