Add caption Why Computers Slow Down However, although computers do slow down after the installation of software, the main reason they get slower is because every year newer software has bigger and bigger requirements. For example: The Windows 98 operating system required 24 megabytes of memory and just 200 megabytes of hard drive space, whereas Windows 7 requires 2 gigabytes of memory and 20 gigabytes of hard drive space. As we learned in How to Back Up Your Data , a gigabyte is about a thousand megabytes so in a 10-year span the requirements for computers have increased 100 times. Who wouldn’t slow down!