help! why my iMac locks up

I am new to macs, loving every minute of the power it has. After upgrading my ram from 256 MB to 1 gig my iMac G5 locks up by suddenly darkening the screen (like everthing goes into background ) and a window in the middle says "You need to restart your computer. Hold down the Power button for several seconds or press the Restart button." This is also in 3 other languages. Can any one tell me what is going on.

iMac G5
1 Gig RAM
OS x.3.9

Its called a kernal panic, it can be caused by faulty ram, I would send back the new ram. How did you go from 256mb to 1GB?

mynameis said:

Its called a kernal panic, it can be caused by faulty ram, I would send back the new ram. How did you go from 256mb to 1GB?

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Bought 2 - 512 MB Memory Simms online. Are you sure it is faulty ram

chefkww said:

Bought 2 - 512 MB Memory Simms online. Are you sure it is faulty ram

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http://docs.info.apple.com/article2.html?artnum=106227

No I am not sure it is the ram, but that is a possiblity, How often does it happen?

Have you repaired permissions already?

If this started happening after you put in new RAM as stated above i would be willing to put money that it is indded the ram macs seem to be pretty picky on the type of memory used.. hopefully the company you bought your ram from has a return policy.

mynameis said:

http://docs.info.apple.com/article2.html?artnum=106227

No I am not sure it is the ram, but that is a possiblity, How often does it happen?

Have you repaired permissions already?

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How do you repair permissions? I am still learning how to use the Mac. And finding out new things every day.

go to applications folder and then utilities folder and then click on disk utility choose your drive in the left colum and then hitt he verify permmsions and then the repair disk permissions

chefkww said:

How do you repair permissions? I am still learning how to use the Mac. And finding out new things every day.

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Applications > Utilities > Disk Utility

Anytime something wierd starts happening, try to repair permissions, it works wonders.

That is a classic symptom of faulty memory. Since it started happening right after you installed new RAM, It's almost certainly the cause.

Contact the company that sold the memory and demand a replacement or refund.

Put the old RAM back in --- you'll get your answer soon enough