Sleep mode can be useful at times when we want to save our laptop batteries, but we do not want to wait for the entire startup routine later.  Most laptop users set their PCs to sleep after just five minutes of non-activity, while the Windows default is just 15 minutes, even when plugged into a power source. However, there are times when sleep mode is completely inconvenient, like when giving a presentation or watching a DVD.  Microsoft’s Insomnia is a free application designed to solve this issue without constantly reconfiguring your power settings. Insomnia downloads as a zip file of just 139 KB.

Read the rest here:
Temporarily Disable Sleep Mode in Windows with Insomnia