suspect it's a typical ignition switch failure... (BTW, alarm horn and car horn are separate items)
Anyhow,
Are you still getting a clunk when you remove key?
Key hard to turn/remove in ignition switch?
Any other odd electrical gremlins: radio stuck on/off, a/c not coming on, interior lights stuck?
If so, simple DIY replacement w/ directions courtesy of Pedro at Pedrosgarage.com
www.pedrosgarage.com/Site_3/Replace_Ignition_Switch.html
