|The drivers loaded in Windows, or any operating system, have nothing to do with whether the computer boots or not. |
Even if there is a serious problem with the video drivers in Windows or other data on the hard drive, or, in almost all cases, even if the hard drive is failing, the computer should still boot and you should have video at least until the operating system starts to load.
The nvlddmkm.sys file is probably a NVidia file - either to do with the graphics card, or to do with the main chipset of your mboard if it has a NVidia main chipset.
When you get Windows error messages that mention a file name, it isn't necessarily that named file that is the problem - often Windows can't tell you directly what the problem is, but instead the error info mentions a file affected by whatever the problem is. You don't delete file names mentioned in error messages willy nilly - that almost always causes additional unforeseen problems. For that matter, deleting files without you knowing what you're doing often causes unforeseen problems. You DO NOT delete what you can un-install.
If the bluescreen has some other info on it
- e.g. STOP: 0X000000xx , often along with A_TEXT_STRING_ WITH_UNDERLINES_BETWEEN_WORDS
- that's what you need to investigate, or ask us or others about.
Probably the most common reason a computer won't boot is the power supply is failing, or it has died completely. A PS that is failing can produce all sortsof strange symptoms including un-explained crashes.
Failing power supplies are common and can cause your symptoms.
Check your PS.
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:
If your problem(s) only started after you ugraded your video card, the original PS may not have enough capacity. If it doesn't have enough capacity, the system usually seems to work okay at first but the PS is constantly overloaded and eventually it will be damaged, malfunction, and it may fail completely.
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.
Another common thing that can cause the computer to behave weirdly or even to not boot at all, is you have changed which ram you have installed and at least one ram module is NOT 100% compatible with your mboard main chipset, or for some more recent mboards, NOT 100% compatible with the memory controller built into the cpu. In the worst cases of ram incompatibility, the mboard will not boot at all, and won't even beep - the mboard appears to be dead.
If you HAVE changed which ram you have installed,
- if you still have the ram that worked fine before install ONLY that ram and see if your problem goes away.
- if you have both old and newmodules installed and you're not sure which ram module is which, or if you no longer have theram that worked fine before....
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 have been fiddling with connections or components inside the case just before your symptoms happened.....
Unplug the case/power supply.
Power off your monitor.
Open up the case by removing the left panel as seen when you're looking at the front of the case.
Check all the connections of the wiring to make sure they are all the way onto their pins and into their sockets, especially the main connector from the power supply. The wires close to the mboard going into the main power connector/socket should be more or less perpendicular to the mboard surface rather than at an angle. Make sure all cards in slots are all the way down in their slots.
A common thing that can happen with ram, even ram that worked fine previously, is the ram has, or has developed, a poor connection in it's slot(s).
This usually happens a long time after the ram was installed, but it can happen with new ram, or after moving the computer case from one place to another, and I've had even new modules that needed to have their contacts cleaned.
See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:
Your problem could be cause by the cpu overheating - in that case most more recent mboards will shut down automattically when the cpu temp goes beyond a certain temp specified in the bios Setup, or built into the bios code, and in any case if the cpu got way too hot the computer usually will not start up again untill the cpu has cooled down some.
While you're in there, if the cpu fan/heatsink has mung (dust, lint, etc.) on it, clean it off, but DO NOT use a vaccuum cleaner to do that (they produce a tremendous amount of static electricity when running, and anything connected to them can discharge that to your components) - use canned air, or an air nozzle if you have access to an air compressor, or an artist's brush that can be used in small spaces, etc. It may be difficult to clean the top of the heatsink under the cpu fan - the most likely place to have mung on it - and the bottom side of the cpu fan blades unless you remove the fan. If you have a case fan, clean that too if it needs it.
With the cover still off, restore the AC power, start the computer and make sure the cpu fan spins - if it doesn't spin, if you're sure the power supply is working okay, don't use the computer until you have replaced it.
If it spins too slowly, and/or if it makes rattling or screeching noises, most likely to be noticed when the computer has cooled to room temp, has not been used for a while, and then is started up, the cpu fan's bearings are failing - replace it as soon as you can.
If you do manage to get the computer to boot again, your problems could be caused by a failing hard drive....
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.