I have a vostro 1015, and a white screen keeps popping up on my laptop's monitor, yet I can still hear the audio playing. What can be the issue of this? How can I diagnose this issue? It probably cause I had my system changed from linux to windows - or it just because I installed the facebook messenger on my desktop, but I just deleted it a few moments ago. What should I do if I still have this problem?

I chatted with technical support online, and they told me to press F2 whenever the dell logo shows up on startup. I did just that, but it still appears. He told me, "Did I try to login on the BIOS site?" what is BIOS site??