|emachines desktop computers usually have a BESTEC power supply. |
BESTEC power supplies have a POOR reputation - they are a lot more likely than most PSs to malfunction or fail completely, and a lot more likely to damage something else when they do that - most often they fry the mboard, only.
BESTEC power supplies malfunctioning or failing are probably the number one reason a emachines desktop computer fails to boot.
Some cheaper models of other brand name computers also use BESTEC power supplies. E.g. HP, Compaq, Gateway, Dell.
There isn't anything particularly inferior about the mboards used in emachines systems. In most cases the mboards used in emachines computers were NOT made by the company that actually made the emachines desktop computer - Trigem, in Korea - they were supplied to the builder by major mboard manufacturers and merely have an emachines bios version on them.
You mention ET-1643 and ET-1641.
I get very few "hits" on the web for ET-1643, many for ET-1641.
If it's ET-1641....
If your computer was made for North America, this list:
says this is your mboard:
It's a ECS model, with an emachines bios version.
If it's ET-1643 it may have the same mboard.
When the mboard in an emachines desktop computer fails to boot after replacing the PS, it's almost always because the BESTEC power supply damaged it while failing.
I recommend that if you buy an emachines desktop computer, if it has a BESTEC power supply, replace it with a better PS as soon as you can, and throw away the BESTEC PS !
You may have noticed there are a lot of ads for "refurbished" emachines desktop computers on the web. Those are probably ones that had the original BESTEC power supply fail on them, and the PS was replaced, probably with another BESTEC one, or the PS and the mboard were replaced, on warranty.
Power failure events often damage PSs. Power failure events often cause BESTEC PSs to damage something else.
Usually a power failure event and/or a PS failing does not damage the ram, cpu, or the drives, unless a power failure event was caused by a lightning strike near your location, or a lightning strike on the power grid near your location, in which case, anything could be damaged.
In most cases there's nothing wrong with the ram that was installed in the mboard that worked fine previously.
People often try installing ram that wasn't installed in a mboard before when their system won't boot normally. That is usually un-necessary and can add to the possible reasons why the mboard won't boot.
Ram that works in another mboard , or any ram you buy or have lying around, may not work properly, or sometimes, not at all - even if it physically fits and is the right overall type (e.g. SDram, DDR, DDR2, etc.; PCxxxx, xxx mhz) for your mboard. In the worst cases of incompatibilty your mboard WILL NOT BOOT all the way with it installed, and the mboard may not even beep - the ram has to be compatible with the mboard's main chipset, or in the case of recent mboards, compatible with the memory controller built into the cpu.
If ram that works fine in another mboard works fine in yours, or visa versa, that proves the ram is compatible with using it in your mboard, but if ram that works fine in another mboard DOES NOT works fine in yours, that doesn't necessarily indicate there's anything wrong with your mboard - the ram may not be compatible with using it in your mboard.
If you still have the ram that was installed when the system worked fine, try installing just that ram.
"One thing I forgot to mention was when I hooked up the emachine for the first time after I put the new power unit in on the monitor it said fan failure right before it shut down after 3-5 seconds if that means anything?"
Most more recent mboards will shut off in a very short time when no rpm is detected by the bios from the header for the cpu fan, to prevent the cpu from frying.
Assuming you connected everything properly - including the power supply connections, and there must be a 3 or 4 "pin" female wiring connector from the cpu fan connected to the proper 3 or 4 pin header on the mboard for the cpu fan - and that you had the original ram in it at the time, and the cpu fan was spinning at the time, that sounds like the mboard has been fried.
(If the cpu fan has 3 wires, the cpu fan header has 4 pins, the 3 "pin" female connector must be connected to the right 3 pins. See this and make sure the wiring from the cpu fan is connected properly.
Motherboard (CPU) 4 Pin Fan Connector Pinout
If it doesn't spin, the cpu fan can be checked by removing it and connecting it to a fan header on another computer - if it's 3 wire, any 3 pin header will do.
It is easy to test for incompatible ram (that wasn't installed in the mboard previously) or damaged ram that has caused your mboard to fail to boot.
Make sure you have a speaker or speakers or the equivalent connected to the mboard so you can hear mboard beeps (see your mboard manual if you need to).
Remove the AC power to the case/power supply.
Remove all the ram.
Restore AC power.
Try to boot.
If nothing else is wrong, you will get no video but you will hear a pattern of beeps that indicate no ram is installed, or a ram problem.
E.g. for an Award bios or a bios based on one, that's often a beep of about a half second, silence for a half second, a beep of about a half second, silence for a half second, continuously.
If you want to take a risk and replace the mboard, there's a very good chance there's nothing wrong with your present ram or cpu.
You can usually find used mboards that were used in emachines computers on the web for a reasonable price, but make sure the ad says the mboard has been tested and has been found to work fine.
You can buy any mboard that your present cpu and ram are compatible with, but if it isn't one that has an emachines bios version and a mboard model that's could have come with your system, it's likely you won't be able to load the original contents of the hard drive by using Recovery disks for your specific model because the program will refuse to load the data.
"Well,I tried installing the hard drive a few weeks ago out of the emachine into my acer and it would show a drive D but couldnt ever retrieve anything..."
What do you mean by that?
If you can see the folders and files on the emachines hard drive but you get "access denied" messages when you try to access anything on it, you need to "Take Ownership" of the folders and files on the drive, to remove the user protection for the folders and files that was enabled when it was on the emachines computer. I know how to do that for 2000 or XP, but not for Vista or Windows 7 - perhapssomeone else can tell you how to do that in Vista. .
You can easily test the emachines hard drive on another computer by using a hard drive diagnostics program.
E.g. Seagate's Seatools will test any brand of hard drive.
Do the long test.
There is a bootable version you can use with any computer that has a working mboard and optical drive, and a version you can install in Windows, if you're testing it on a computer that has a working Windows installation.
If the hard drive itself tests okay, any data problems found can be fixed, one way or another.
The optical drive(s) and floppy drive if you have one, and any cards your have in slots, can be checked out by connecting them to a working computer. In the optical drive(s) is(are) IDE, you may need to change a jumper setting on the drive.
If you see any physical damage of the contacts on the ram or cards, or in the slots on the emachines mboard, or on the drive's connector pins, or on the connectors of the original PS, then probably more than just the mboard has been damaged.