Stalking in the work place.

I was wondering what rights I have. Here is the situation, a co-worker was stalking me and hacking into my computer on a daily basis for a period of almost 2 years. I work for a very large corporation with many levels of management. I spoke to my manager about this, she did nothing, so I went to her director, who also did nothing.
I spoke to the I.T department and my director's director. Basically I
spoke to anyone who would listen and I thought would be in a position to take action against this fellow employee however no action was ever taken. I asked them repeatedly to scan my PC so I could prove to them that this was happening. I was stalked for almost 2 years and at times truly scared, however no one took the issue seriously. What rights do I have if I want to sue my employer? Even though I have no real evidence, but that's not for lack of me trying to obtain evidence. I live in Toronto Canada.