I've never used Ninja and I'm not a scalper. But there are plenty of both around here and you're in the right place to ask about hardware for trading purposes. You can have multiple browsers on any pc. Go ahead and install Firefox, Chrome & IE all on the same box; it's not a problem. Winston has given you the best advice. He knows what he's talking about. If you shut off all that shit that's made for 13 year old girls to send butterflies with glow and soft edges to Grandma, you'll have what you bought & deserve. Good luck trading.
Ran mcafee for years and kept having virus problems and it was a resource hog. Now I run this for av http://download.cnet.com/AVG-Anti-Virus-Free-Edition-2012/3000-2239_4-10320142.html and this firewall http://download.cnet.com/ZoneAlarm-Free-Firewall/3000-10435_4-10039884.html?tag=mncol;1 and run these 2 spyware cleaners once or twice weekly http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html?tag=mncol;1 http://download.cnet.com/SuperAntiSpyware-Free-Edition/3000-8022_4-10523889.html?tag=mncol;3 for browsing you cant beat firefox for speed and security http://www.mozilla.org/en-US/firefox/new/