Are you fixing up a computer to give for the holidays? Kicking around a 3- to 6-year-old box that you want to breathe new life into? I've figured out a few ways to keep them going, especially in my job where I sometimes act like an OEM, building and reviving systems that require a little TLC. Power suppliesThere are a lot of sub-par power supplies floating around: usually ones that come with cheap cases. Reasons you might need a new power supply are plentiful: Windows BSODs; Windows\/Linux "hard" crashes; burnt plastic odors. I've learned how to distinguish the ones more likely to work than not. 1. Use 80PLUS when you can. Modern power supplies are required to convert at least 80% of the wall AC into equivalent DC. This requires decent parts and tuning to accomplish. Decent and cheap power supplies can be found, that honor 75-80% efficiency, without breaking the next rule.Total 12V+ output should exceed your 3V+ and 5V+ outputs. Numerous power supplies claim to be a certain wattage, but if you convert their "A" (amperage) numbers from the different "rails" (the different kinds of output), that number may exceed the stated output. If you look at your cabling, you'll notice your motherboard and video card prefer 12V power (fans and drives can take up the other rails). Watts = Volts x Amps (thanks commentors for pointing out the correct formula); a power supply with 30A of 5V+ power, but only 15A of 12V+ power, is pretty useless to newer systems. Multi-rail 12V+ systems are usable: be sure the individual rails have enough amps on them to power either your CPU, or your video card (not always given which rail is powering which set of wires). 2. Other hardware 1. Lower CAS memory is better for responsiveness. 667mhz memory running a CAS # or two lower than 800mhz parts with higher CAS may feel more responsive.IDE optical and hard drives: go all SATA if you can. Bandwidth considerations aside, even a SATA1 drive should help the system be more responsive than with an ATA100 or ATA133 drive. 2. Get away from Operating systemsGet rid of XP if you can! Its networking stack is old, and it\u2019s pretty vulnerable to viruses.1.If the system has at least 1GB of RAM, it can run Windows 7. You should be able to get a new or upgrade copy online cheaper than a regular store. If your CPU supports it (test with HWINFO32 or CPU-Z), install the x64 version for best results.2. If the system has 256MB, or more, and\/or you're considering gifting it to someone who isn't computer savvy, sneak Linux on it anyway! Old systems should use XUbuntu; casual users Ubuntu; multimedia buffs Linux Mint or Ubuntu Studio. Looking to play a particular game on it, or run an old app? Check the Wine Application Database; it\u2019s not uncommon to play a Blizzard or Steam game on a Linux box these days (I personally have gotten Team Fortress 2 to work with little effort). You can also tweak a WINE setup using "winetricks".Changes for Windows 1. Look at tips I suggested for improving networking performance.Make use of ReadyBoost: it'll work on compatible flash drives up to 4GB on Vista, or 8 flash drives, up to 256GB total, on Windows 7. A lot of people mistake this functionality as additional RAM: it is more like making your own hybrid hard drive. The flash memory acts as a buffer for operating-system components otherwise loaded from the HDD.Aero graphics will work on a mid-range video card: considering adding one if you're using integrated\/on-board graphics; $60 is a good average to spend for this kind of application. If you have no PCIe slot, there are numerous NVidia-based solutions available. If you have a PCIe slot, my personal preference is for AMD HD5xxx-based cards; this has been tempered by failed attempts to add NV cards to Dell desktops from the 2005-2008 era (quirky BIOS conflicts involving on-board video or add-in cards).consider using 64-bit video playback software. Windows Essentials Codec Pack started offering 64-bit builds of open-source playback tools.please get them away from Internet Explorer! My own recommendations are for Firefox, Chrome, or (for the stubborn) using IE with the Chrome engine.Non-official sources for drivers and softwareFileHippo: I've used that site for years to find common, updated (sometimes beta) drivers and software.Guru3D: useful for video card tweaking and tuning.Station Drivers: you can find Intel and other OEM drivers not normally found on their own websites. 2. 3. 4. If you're running a x64-based (64-bit) system, 5. If you're supporting someone who isn't computer savvy, 1. 2. 3.