As well, a momputer has nothing fancy; No overclocking, no water cooling, no pricey, bleeding-edge hardware or a need to maintain on a daily basis. It must be powerful enough for small flash games, and the occasional flash advertisement. First-time PC users should also have the default browser (or different, easier one) pre-supplied with an advertisement blocker, and for the especially typo-prone, a system-wide spellchecker may also be on call. Keeping things simple and budget will ensure you don't break the bank, and give your mother a PC she can do basic tasks with.
Examples of momputers from OEMs would include netbooks, nettops, budget desktop PCs and budget notebooks.