|"...he's pretty smart about pcs..."|
Lots of people know how to use the software they use well - I'm certainly no expert about that regarding some software - and how a computer or the operating system is supposed to work, but that doesn't necessarily mean they know what to do when there's a problem.
"....he couldn't get on the internet with ZA ...."
ZA could cause you not being able to connect to SOME sites on the internet but's it's very unlikely to cause you not being able to connect to all sites on the internet, unless he really buggered up it's settings - it's much more likely something else was wrong, especially if he hadn't been messing with settings in ZA since he could last successfuly connect.
"....Rebooted again and saw the error that there's a problem in the windows system files and now it WON'T BOOT UP AT ALL!"
Did he make note of what the error was? If so, we need to know what it said.
"....it WON'T BOOT UP AT ALL!""
When people say that it's often NOT clear what they mean.
When we who answer say that, we almost always mean the mboard will not boot, but that's not necessarily what people who have posted here are trying to say.
Does he mean the mboard will not boot,
the mboard does boot, he has video, but he can't get into Windows anymore
- the two are very different situations.
If the mboard does boot, he has video, but he can't get into Windows anymore -
The hard drive may be failing - if it is, trying anything else may be a huge waste of time.
Check your hard drive with the manufacturer's diagnostics.
See the latter part of response 1 in this:
(thanks to Dan Penny for this link:)
Hard Drive Diagnostics Tools and Utilities
If you don't have a floppy drive, you can get a CD image diagnostic utility from most hard drive manufacturer's web sites, but obviously you would need to make a burned CD, preferably a CD-R for best compatibilty, on another computer if you need to.
If the hard drive itself tests okay, any data problems found can be fixed, one way or another.
If the mboard does not boot....
As I said above emachines desktop systems are more likely to have a problem with their power supply, especially if it's a BESTEC model. You can get all sorts of strange symptoms before the PS has failed completely. If it HAS failed completely, it's more likely it has fried the mboard while failing. It it hasn't failed completely, I recommend he does NOT try to use the computer until it does fail completely!
Failing power supplies are common and can cause your symptoms.
Check your PS.
If they work, they often partially work, fans and hard drives may spin, leds may come on, yet you may get no video and the mboard will not boot all the way.
See response 4 in this:
If it is failing, you can usually replace it with any decent standard sized standard ATX PS with the same capacity or greater.
Standard (PS/2) power supply size - 86mm high, 150mm wide, 140mm deep, or 3 3/8" h x 5 7/8" w x 5 1/2" d , or very close to that, though the depth can be more or less for some PSs.
Don't buy an el-cheapo PS.
See response 3 in this:
Your power supply must have at least the minumum capacity required to support a system with the graphics card you are using installed, or the max graphics card you might install in the future.
(Onboard video - video built into the mboard - IS NOT A CARD!)
You can go to the video card maker's web site and look up the specs for the model - often under system requirements - the minimum PS wattage, and, more important, the minimum amperage the PS must supply at 12v is stated. If you don't find that, any card with the same video chipset including any letters after the model number has very similar minimum PS requirements.
If you want to cover any possible video card, a minimum 600 ot 650 watt power supply will handle any current high end video card, or even a X2 card (two video chipsets on one card) or two cards in two slots.
If he tries another PS and that doesn't help
- if the PS failed completely the mboard may be fried. Used mboards from emachines systems are often available on the web for cheap, if he wants to go that route, but make sure the mboard has been tested and is known to work. Usually everything else - cpu, fans, ram, drives, cards - is still okay.
He probably won't be able to use the Recovery disks for the emachines model unless the mboard has an emachines bios version, and/or is one of a small group of possible mboards the disks support you using.