Power Supply Question

Yes. Downloading and playing games will increase power demands.
Unfortunately most mfg. will install the bare minimum size power supply, memory, and other parts in their machines. Also, power supplies tend to weaken with age and heavy use. It is possible that the psu has weakened and may be causing this problem. Another issue may be heat build-up inside the case. You can remove the side panel of the case {for better ventilation) while operating the computer to see if this makes a difference.
If you tell more about your machine, I'm sure you will get many recommendations as to how large a psu you should have as a replacement.

There are so many variables in the process of getting a new power supply that it boggles the mind. So, a little research is needed beforehand.

With that, I'm using the power supply selector available at http://www.pcpower.com/Power_Supply_Selector.html. I'm using that one because the company in question is highly regarded in the industry and because I use their products. I can personally vouch for the reliability and ability of PC Power and Cooling PSUs to exceed minimum rated power. Similar selectors are available at other PSU makers, so feel free to look anywhere you desire. Just remember NOT to skimp on a PSU; saving a few bucks here just isn't worth it.

1. Go to http://www.belarc.com/free_download.html and download the Belarc Advisor. It's free and will tell you exactly what you have in the way of processors, video cards and hard drives - which you'll need to know.

2. Go to the manufacturer's web sites of the processor, video card and hard drive makers and look up the specs for the gear you have in your PC. This will give you an idea as to the amount of power the components consume under full load. Write all this down.

3. Go back to the PC Power PSU selector page and look up their recommendation. Even if you choose not to buy from them, by looking up the specs for the recommended unit, you'll have the information that you'll need to buy a nice PSU from Antec, Thermaltake or some other maker.

NOTES:

1. The PC Power page recommends PSUs based on the real need to have a sufficient power reserve for periods of heavy usage. In the same way that an audio amplifier that's quite acceptable at lower volumes will unacceptably distort and overheat at higher volumes, so too will a computer PSU that works just fine at low loads distort and fail to adequately power components at high loads. In an extreme case, this can damage a processor or video card.

I would consider the recommendations to be a minimum acceptable safe choice. If your budget allows, go a little higher - it'll hurt nothing and you'll be even more reassured.

2. If you happen to own a Dell computer, be very, VERY cautious. Since 1998, Dell has used a wiring scheme in its motherboards and PSUs that is nonstandard. Using a standard PSU in a Dell is a recipe for fried motherboard and processor.

I've included a Google search for "power supplies for Dell computers" to same you a little time: http://www.google.com/search?q=power+supplies+for+dell+computers&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a. This search was done in Mozilla Firefox; you may have to manually enter the search words if you're using another browser.

Hope this helps,

Paul