I have a HP Vectra VL420MT that I was adding some ram too.Well I didnt have my glasses on and put it in backwards and turned it on.It made 3 strange noises then 3 beeps.I pulled it out and put it in correctly and it still does it.I triend some different sticks of ram ,,same result.I took all of the ram out and same result.It is not seeing any of my ram.Did I short something out and now need a new motherboard?? Thanks for any help.

Yes, you probably shorted out your memory slot. the beeps it is making is an error code. try turning it on again and write down the error code. it should be like 3 short beeps, long short long, short long short, or something like that. take that info and look up the error codes of your motherboard, that will tell you exactly what went wrong.

but more than likely you ruined your motherboard and need to buy a new one. may i suggest one with ddr2, you can't put those in backwards unless you are really trying.

Hope this helps

oh yea,
Next time you want to upgrade your system, let a professional do it.

Yes I was afraid that is what I had done,,Thanks for the help and as or you jermaghs07,,,Iam a proffesional ,,,, its just when you get older and dont have your glasses on you seem to screw up more;)