Help Please!!! none of my lights are working!

Hello everyone , I recently purchased a 1990 grand prix se and while in the process of fixing the car i have somehow caused my headlights, dash lights and hazard lights to crap out. I suspect that i probably have broken a ground strap somewhere but i am at a loss as to "where" is.
It could be somthig else entirely but I just don't know .
I would greatly appreciate any help you could provide.

what were you doing to "fix" it? It sounds like a fuseable link burnt due to something being shorted. Check the battery jump post on the drivers side near the strut, and there should be 2 or 3 smaller wires attached to the post there. If any look burned or feel soft, you found your problem. Go to any auto parts retailer and buy the appropriate guage fueable link, and splice it in place of the burnt one.

i checked the fusible links in that area and they are all fine. the fixing I was doing was a basic tune up, throttlebody clean , removed and cleaned egr valve, replaced the horn relaynothing out of the ordinary.I had the pass side door panel off to remove the power mirror. There is no power to the tail fuse which is the hot fuse for the switch . so unless there is another fusible link somwhere else???

Also check your fuse box and under hood relay center, maybe you blew a main fuse.

Thanks for all your advice . I found the problem today. there was a choroded broken wire in the front harness that was shorting. fixed the wire and voila !! let there be light!!