np man. just helping out.and just a few suggestions and comments.
if youre not satisfied with coverage, can always bump up voltage and overclock it. just dont get too excited and blow it up. i would even suggest asking for some settings on the ddwrt forum. also, if you have another router (preferably another ddwrt'd router) you can set up repeater bridge mode and have it spread the signal even further and use one of them as a gateway to pass out IPs for both WLAN and LAN.
lastly about the random BSODS, i would:
1) scan for viruses, malware, adware etc. with antivir and superantispyware.
2) test of stability using OCCT for CPU stress and monitor cpu temps with HWmonitor. As i said before, it could be because its a P4 and its overheating. If its reaching anything over 70C it will BSOD to prevent melt down. then you need to clean that mofo ASAP.
3) run memtest to see if memory is kicking dirt.
4) if all is okay, then suggest a reinstall of windows because probably of years of abuse and registery is all f**ked up. because by the looks of it, the drivers werent install correctly. oh yeah and i would install the latest driver for your video. its either an intel or nvidia not sure which one because i didnt really look.
good luck and have fun with ddwrt =)