pc won't boot

[Dadsgrice]

Just changed the power unit in my pc went to start but it won't go through boot sequence there is power to system but nothing appears on monitor and does not go through boot up.
Any ideas plz

[johns0]

Did you plug in the 4-Pin Power Connector?Wont boot if thats not connected.

[Dadsgrice]

pluged in main one into m/board but that is all also makes a beeping noise

[aedipuss]

does the video card need a power plug inserted?

[redwudz]

Basic question, why did you change it? A problem or just a upgrade?

Power to what part of the system? Fans? Optical drives? Does your hard drive spin up?

BIOS beeps? Can you describe them? Long beeps are usually a RAM problem.

I would reseat all PCI cards and all connectors, and your RAM modules. Sometimes they get knocked loose.

Then if that doesn't help, unplug all cards except video and all drives except the boot drive and try again.

Or you may just have a bad power supply.

[bevills1]

I've had to do what redwudz said in his second last sentence on more than 1 occasion. Don't know why it works, but it's worked every time I've had the problem except for once with a new mobo which was tested as a bad mobo at place of purchase. Thus I'd suspect redwudz bad power supply assessment is correct if that suggestion doesn't work.

[Dadsgrice]

I have no where for hte four pin connector to go to all drives have power have swapped ram round have swapped power connectors for drives cpu fan spins. it is just as though something isn't connecting somewhere put power unit into another pc works also worked in this one before i removed it but now it won't.

[DarrellS]

The four pin power connector has to go somewhere. I was looking on newegg and most of the jetways have an eight pin power connector on the board instead of four. Better check your manual on how to hook this up.

[bevills1]

The 4 pin connector is used to power the CPU on newer systems, but older systems don't require it. You need to try redwuz suggestions to determine what the problem is. Otherwise you're just wasting time and may as well be spitting into the wind. Actually I disconnected even the boot drive to see if I could get into BIOS in the instances cited in my first 7/11 post, and I suggest you try the same. You might be thinking that's much trouble and thinking it won't work which is what I thought when it was first suggested to me, and I was surprised when it did work.

Edit: I've also had some pretty unusual coincidental failures too. For example I once had a floppy drive fail when I upgraded a system with newer mobo and CPU. You may have had such a coincidental failure of some part when the PSU was replaced. Trying the suggested procedure should either get you going again or tell you that you have some kind of hardware failure.

[TBoneit]

How about the Motherboard model so someone can look it up and really determine if it does in fact need the 4 pin power. As I remember it that connector can be hard to spot on some of the Jetway Mobos.

[bevills1]

A Gigabyte GA-EP35-DS3P mobo is shown in OP's profile if that's current. I have an AMD 2600 which doesn't have that connector and an AMD 3400 that has it. That Gigabyte being an 1800 would likely not have it, but check to see would be the only way to know.

[DarrellS]

A Gigabyte GA-EP35-DS3P mobo is shown in OP's profile

No, that is my profile. His profile says Jetway but does not give the model. BTW, the Gigabyte does have the four pin connector.

[Nelson37]

OP has failed to answer the extremely critical question of WHY the PS was replaced in the first place. Also number of beeps, with short or long, in the "beeping noise".

Did the old PS have the extra 4-pin connector would be the next question. Doesn't mean it was in use, but if there wasn't one and it worked before then we can stop spinning our wheels.

To the OP - Answers to important diagnostic questions can only come from YOU. The amount of effort you put forth into this is directly related to the amount of effort spent by users here in solving your issue. If you don't think these answers are necessary, that would indicate you know enough to solve it yourself.

Talk about coincidemtal failures, just had this one - Mobo fan connector voltage drop caused fan speed low leading to overheating reboots. Used adapter to standard Molex connector, causes a BIOS message requiring F2 keypress. This revealed a scheduled evening reboot for a long-ago backup software, no longer used. In the middle of this, a Norton update to the Norton update software failed, causing a reboot in the early afternoon, at almost the precise time the previous overheating caused failure. This reboot would have gone unnoticed except for the F2 requirement, which if not met in 30 seconds caused shutdown. Symantec out, AVG in, Scheduled reboot eliminated, fan speed and CPU temps now OK. Royal PITA.

My guess on the OP would be that he missed the aux power connector, and may well now have a memory chip mis-installed or similar other error. Additional information required.