I took blood thinners for 1 year in 2006. the last 5 years i bruise so easily on my arms. it takes a long time to heal. could the bruising be caused by the blood thinners i took?

No. They are long out of your system. If you're not having widespread bruising, nose bleeds, gum bleeding,etc, it's unlikely you have a coagulation disorder. I would attribute the bruising to the thin skin on your forearms or back of your hands. Also taking aspirin,anti-inflammatory meds like advil or aleve may play a role. Vitamin C deficiency in your case probably is not an issue.