I can't download a program because I get a notice that my computer must be 64 bits. What should I do?

It means that your computer runs in an older 32 bit format, which you'd have to reinstall Windows to change unless there are options to download it in 32 bit. Your installation disk should have both a 32 bit and 64 bit version of Windows on it. Your CPU has to be able to cope with a 64 bit version of Windows for it to install, though. You can check if you can run 64 bit Windows by opening the Start menu, clicking Control Panel, Performance Information and Tools, and then Performance Information and Tools again. Then, click view and print detailed performance and system information, and look at 64 bit capable in the System section. Remember to back up your files if you do decide to upgrade!