It did not take long at all to install with Windows Update. I do not remember exactly how long, but was a lot less than 30 minutes, maybe 5 minutes, 10 minutes at the most. Also, I did not disable any anti-virus programs as I did not have any reason to do so before reading this blog, and did not have any problem with that. I do not think I have a particularly fast system; there are allready faster systems on the market since my notebook came out. My processor is an Intel Core 2 Duo 2.2 GHz, RAM is 4GB, on about a 1 year old HP Pavilion dv6 1355dx notebook. The operating system is Windows 7 Home Premium 64 bit. I have not had any problems since Service Pack 1 was installed 3 days ago.