88 4runner psyco electrical issues

Hey everyone! I have an 88 4runner v6 3vze.

I was installed a new stereo and I had it running for about 2 days and then one morning I started it up and none of the gauges where working (except speedo). Also, the trans. seloniods and all the turn signals, rear (but not driver) windows don't work nor does overdrive. Geez this is confusing. I had a terrible battery that I just replaced after this stuff happened but, I did not remedy the electrical wierdness. I have a reletively new alternator but, who knows?

Any help would rock!

Oh! I forgot to mention that the sound system is 800 (continuous) watts. Is that too much for a 60 amp alternator to handle. My amps both have 40 amp fuses.

Thanx again---------ty