I need recommendations on a New Computer

Right now I have a generic computer that was built in 2002 in Ohio and things added in 2005 in Wyoming. I needed a new video card and I had one added but it did not work and the guy tried to put my old one back in and it messed up my computer. Every time I turn it on I get a New Hardware message that says there is a problem. The Multimedia Audio Controller has a yellow? by it.
This computer has Windows XP Pro, AMD Duron 1.19GHz (started out with AMD Athlon 1 GHz), 512 MB RAM, video card 16MB, Sony DVD RW DRU-810A (added 2006), Display Adapter--NVIDIA Vanta/VAnta LT, Network adapter SiS 900-Based PCI Fast Ethernet Adapter.

I am trying to run Better Homes and Garden Designer Suite 6.0 and when I try to do the 3D view I get error messages. I do have a Dell Inspiron 9300 laptop that I purchased in January and it runs the program okay. I did have my Desktop and laptop networked and it seemed to work okay until I had the video card changed.

My Laptop is
Dell Inspiron 9300, Pentium M 760 (2GHz/533MHz FSB)
17" wide screen
2GB, DDR2, 533MHz 2 Dimm, for Inspiron 9300
ATI Mobility Radeon X300 64MB HyperMemory Video Card
100GB Ultra ATA Hard Drive
8X DVD+/-RW Drive
Intel PRO/Wireless 2200 Internal Wireless

I have read on some forums not to buy Dell computers. I live in a remote area and do not have choices but there is a guy about 35 miles away that is authorized (?) to build Dell computers. He called me yesterday and told me he could get an OptiPlex GX 620, 3.4gig, dual core, 1 gig ram, 19" monitor, 160gig hard drive, DVD (don't know what kind), no sound card or video card which would not do for me. The sale price he quoted was $1500.

I want as much as I can get in my Desktop so I won't have to worry about it for a very long time. With the information, can someone tell me what to look at? I do not like HP's and do not have any computer places without driving 135 miles one way or 200 miles the opposite way.

I also have embroidery designs on my desktop and lots of photos.

I would appreciate any information you can provide.

Thanks,
Sue in Wyoming