I have a 5 year old Dell desktop that came with 512mb DDR Sdram PC3200 400mhz (2 blocks of 256mb) memory. I just installed 2 blocks of 512mb DDR Sdram PC3200 400mhz for a new total of 1GB but now the only programs I can access on the puter are the Internet my VIRUS program and Windos Explorer. I cant open Outlook, Outlook Express, Word, Excel or any other program that I have.

When I try to open these progams by double clicking on their icons or by clicking on START  then All Programs then the name of the program,  I get "Failed To Initialize Properly"

I believe the new memory is just a generic brand, its certainly not Kingston or Corsair.

What the HECK happened   Should I just reinstall my old memory ??I would recommend doing some testing with the memory. Maybe the machine was only meant to handle 512mb on the motherboard especial a pc running sdram that is 5 years old, or maybe the speed of the new memory is not the correct speed for the motherboard and the MOBO (motherboard) can only handle PC3200. Try just one STICK of 512mb of the the new memory on the motherboard and see if that changes anything. If all else fails you could just stick with the old memory. But if you find that my troubleshooting is wrong and your motherboard is CAPABLE of HANDLING the amount of memory you want and the speed also I would try to reinstall Microsoft Office. I would first do some investigating to see if my motherboard is capable of that certain memory though, for I know I would rather have a gig then only 512mb Generic memory gives you what you paid for...
However you could try 2 things:
Remove all the Old RAM ...
Go to Start/Run and type in sfc /scannow and hit Enter...have your XP CD handy.Well, The max mem the computer manual says it will hold is 2GB. The proper type is PC3200 which is what came out of it and the 1GB I put into it is also labeled pc3200. The old and the new were also labeled 400mhz so I think I got the correct type. 

However, I knew I was taking a chance when I bought generic but a couple of friends had good luck with there generic mem purchases.  The only thing I 've done is put the old mem back in and the puter is working fine now, I just wish that mem upgrade would have worked.  I will return the mem I bought and I guess I'll just buy some more through the Dell website.

You know, what might have been a problem is that the old mem was rated as DDR2 and the new mem just said DDR. Is  there a huge diff between DDR2 and DDR ??
Yes.yeah....

that would be the cause of the issue...