system is tanking!

Hi all,

Hope someone can help me here.  In January I bought a Dell Dimendion 8250. About a month later I purchased a Lexmark X85 all-in-one from Dell. Everything was chugging right along. I was scanning and e-mailing photos, printed some of my baby pictures for my daughter (I have a 19 year old grandson so am no chicken). then about 3 weeks ago the memory failed and the computer was dead in the water so to speak. A Dell technician came to my house and installed new memory (512 RD RAM). Oh yes, I have WinXP pro as an OS, plus the old lady likes games so I've got the ATI Radeon card - the 9700, and the Audigy 2 Sound card. Other than that, it's just a nice computer with more hard drive space than I will ever use, a gift from Dell.

For about 5 days after the new memory was installed everything was back to normal, then stuff, bad stuff started happening. First, I lost my printer drivers. Couldn't re-instal them to save my life. I called Lexmark. They had me run a self test since the printer can scan and print without the computer. It did just fine. So then I changed the USB cable to a new one since bad cables have been the source of so many of my earlier computer troubles. Nothing happened. An IT friend told me to attach the USB cable to one of the front USB ports, so I did and hooray, the printer worked - for a bit.

I was on the phone to Dell tech support when 1, the printer drivers got lost, 2 the CD-ROM drivers got lost, 3 my Bellsouth ISP drivers got lost, 4 my DVD drivers got lost. It was clear the system was dissolving as I spoke to India. She couldn't help me so gave me to her supervisor. He told me it was either in WinXP or I needed a new motherboard. OK, so I re-installed WinXP and immediately thereafter installed the device drivers. Everything there installed except the USB drivers. Another Dell technician gave me a link to an Intel download of those drivers. They downloaded just fine but they won't install. So no printer, an unstable mouse and No way to plug in my digital camera. Some of  my software installs no problem, other software won't install at all. Some of it arrives on the computer as a partial set of files or corrupted. Trying to uninstall the corrupted files is impossible, the system freezes. I haven't a clue what to do anymore. I ran the advanced system diagnostic today at Dell's request. Everything came up OK except the CD-ROM and DVD drives won't recognize any of the media that the discs I used for the test contained. I might add I'm having the same trouble installing downloaded drivers and software as CD software. So, it's the software, but it was caused by a hardware failure. Any thoughts about what I can do to fix this other than throw the computer out of my 25th story window and starting over again with a home build?

Thanks a million for any and all help the resident geniuses have for me.

Carole