99' Porsche Boxster power but no start

I got a 99 boxster that i recently started fixing up after sitting in a garage for about a year. Got a brand new battery and changes positive battery cable (since it was far gone). After that I plugged in the battery and power went through but no start. It would click super fast and flash dash but nothing else. I noticed the seats wouldnt move foward or backward from being electrical but I also did get a new battery and didnt let it sit to drain. Any thoughts ?

Check your voltage it should be at least 12.4V. Under this it may not have all the power needed to start the car but enough to light up the dash.

A fully charged battery should read > 12.6 volts. A charging system that is operating normally should produce about 13.8 to 14.3 or more.
Battery Voltage and State of Charge:
12.66v . . . . . . . . . . 100%
12.45v . . . . . . . . . . 75%
12.24v . . . . . . . . . . 50%
12.06v . . . . . . . . . . 25%
11.89v . . . . . . . . . . 0%

It sounds like the starter is not kicking out fast enough before It starts to spin. As described it sounds like there is no crank and by extension no start as distinct from cranking, but not firing. If the latter is a more apt description, there are a whole host of other checks that need to be done.

I would check that all connections to the battery are solid. Then that all grounding straps are soundly connected and not corroded, note there are more than one.

I would attach a charging block or another vehicle to the battery and try again. Unlike newer cars, there are fewer computers to worry about, so you should be able to jump start the car safely with jumper cables.

If none of that works, you will need to pull the starter and check that for issues.