I've been using Power Tree S650BX UPS for about a year now. It has worked perfectly when the electric power went off. It has no driver CD but given that it hadn't caused any problem [even if it's not configured on the operating system] I didn't bother to look for its drivers on the internet. Last week I changed the operating system from XP to 7 and when the electricity went off (today) the UPS didn't work and the computer shut down immediately and incorrectly. I wonder why this happened. Is it related to the OP and the need for configuration on the system? I don't know where I can download the drivers for free on the internet [if that's what's causing the problem]?