A Windsor man has pleaded not guilty to a number of charges including attempted murder.

It stems from an incident in 2015 where a woman was found in a tub with stab wounds to her chest.

Monday was the first day of a trail that is expected to last several days.

Kenneth Sparks, 60, pleaded not guilty to assault with a weapon, aggravated assault and attempted murder.

On the evening of March 20, 2015, police responded to reports of a woman screaming at an Ottawa Street apartment.

When officers arrived, they found Deborah Bondy covered in blood with Kenneth Sparks standing next to her.

She told police sparks had assaulted her with a weapon and he was arrested.

Shortly afterwards police found another woman, Sherry Beachard in a nearby building, laying in a bathtub with stab wounds to her chest, suffering from a punctured lung.

Police said the two women and Sparks were all known to each other.

On Monday, Deborah Bondy testified the group was together to celebrate her birthday.

She had gone to the washroom, heard an argument and came out to find her friend covered in blood.

While on the stand today Bondy also said she was in a state of shock.

Bondy then said she was struck in the head and had lost consciousness at least three times.

Several people are expected to take the stand in this trial, including neighbours.

Two weeks have been set aside for the trial, but Sparks' defence lawyer Laura Joy anticipates it may last a week.