I dought anyone will read this, but I managed to solve the problem, and I know why you never went to Linksys Support. They aren't exactly pros...
But anyway, to fix the WRT54G DHCP problem, you need to download and install the firmware update to upgrade the router frem ver. 3 (or 2; not sure) to ver. 4. Mine's working perfectly now.
Just to add: I had gone to my local Office Depot in search of a network card for my laptop. I asked an employe for the cheapest one the had- but it wasn't made by Linksys. He warned me that it would probably not work as non-Linksys products don't work very well with Linksys prodcts. I assured the man that I would probably get it to work.
I've now decided that I should have told him that even Linksys products don't work with each other.