I have always had great luck with Dell. Last year, I bought a Windows 7 computer from Dell. It kept rebooting and online support, though very helpful, couldn't resolve the issue. They sent an in-person repairmen to replace the motherboard and fan. Didn't help. At my request, they sent me a new computer -- no hassles at all. This PC has run perfectly.
I had my previous Dell for about 10 years and never had a single problem with it -- even running Windows ME.