Improve computer speed & reliability

I need help...I'm teaching a national conference next week and need my laptop to be in tip top shape...this is NOT my forte'...hope someone can help. I don't need system updates to start in the middle of my presentations or unnecessarily waiting on my computer to respond.

If it matters...will be highly QuickBooks 2014 intensive as far as software as well as powerpoint.

Any help would be greatly appreciated...here's my log...

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows 7 Professional, Service Pack 1, 64 bit
Processor: Intel(R) Core(TM) i3-3217U CPU @ 1.80GHz, Intel64 Family 6 Model 58 Stepping 9
Processor Count: 4
RAM: 3983 Mb
Graphics Card: Intel(R) HD Graphics 4000, 1799 Mb
Hard Drives: C: Total - 454712 MB, Free - 374211 MB;
Motherboard: Dell Inc., 06RYX8
Antivirus: McAfee Anti-Virus and Anti-Spyware, Updated and Enabled

Thanks,

Brandon