Re-using old components?

I absolutely wouldn't suggest anyone use a 10 year old PSU under any circumstances. Not even if it sat in a box for that whole time.

What PCs pull from each voltage type has changed completely in that time, making 10 year old PSUs provide power pretty much opposite of how people need it now.

I would definitely tell him to get a new PSU from Antec, Corsair, Seasonic, or XFX only. No other makers will do.

The hard drive from the old PC will probably be standard ATA which uses a ribbon cable and it may take considerable effort to find a motherboard that will support this. You could end up putting it on the same ribbon cable as the CD drive which would hurt performance.

I would instead just buy a whole new SATA hard drive as well. Your 10 year old hard drive will probably only hold like 10 or 20 GBs worth of data, guesstimating, which probably means you will be able to get an OS on it and like one game and that is all. Just get a cheapy 250 GB or something instead of this.

The case is probably fine, but it will not have optimal cooling which means the parts will wear down faster, especially the PSU. Cases 10 years ago pretty universally used top mount PSUs which takes all the heat out of the case and sucks it into the PSU before blowing it out the back.

That greatly reduces PSU longevity in general.

Such cases were built for a time when heat output was 90% less than it is now, so while it may have been good enough in the past it may not be good enough now. There may also not be room for such important things as side fans and rear fans to assist in keeping parts cool and sucking heat out of the case.

Really, I would just not use any of those parts.

You can get a reasonable gaming PC on the low end for under $300 and it will just work so much better and last so much longer if you can go that high than if you try to use the older parts.

+1

The case shouldnt be a big deal. Preference really and there isn't anything ground breaking in terms of cases missing aside from bottom mounted PSU.

The PSU would need enough Watts to run everything. If it died it wouldn't cost much to replace in a jiffy.

The HDD would mean you will be using a mobo supporting IDE which you should be able to get for cheap.

I would think you can use those components to help reduce the price but those are not very expensive parts in terms of a build.

The question isn't how much it costs to replace the PSU, the question is how much it costs to replace the motherboard, processor, or video card it takes down with it.

Yeah, an old and possibly low grade PSU may or may not have any protective circuits in place.

Ok so out of the two builds posted in that link which one would be best for gaming if playing mostly games like Red Orchastra 2 , MW3, etc. I have always gone with AMD so I have relatively little information for him on using a Intel for gaming from personal experience. Thanks

A HD 5830 is better than the 6770 for the same price.

In any event, I would go with the AMD one with a better motherboard.

I have been trying to talk him into splurging a little extra for the 6870. If there is one thing I have learned over the years its to buy the best graphics card possible.

The referenced builds are both reasonable.
I do think that a intel sandy bridge 2100 might be stronger from a cpu point of view. Read this article on <$200 gaming cpu's:
http://www.tomshardware.com/reviews/best-gaming-cpu-cor...

The integrated graphics may be sufficient for light gaming initially. That would give you some time to shop for a good graphics card.
Try e-bay, looking for a reputable seller of a used high end graphics card. Whenever I upgrade, that is where I sell my old card, and the buyers always get a great deal.