Dodgy Brake Switch
 

I am new on here as I have only recently Bought my 2005 Boxster. Houston, I have a problem. I returned to my car yesterday and noticed the Brake lights Illuminated, Windows a quarter way down and the spoiler extended. I got in and it started fine, but with PSM system Failed message and illuminated. drove it around the Block and still the same. Then Retracted the Soft Top fully, tried to raise it and it stops short of the windscreen. The windows will go down fully but only come up 3/4 way. Now the Roof will not move at all. Does anyone have any ideas???? Also Brake lights are still on even with ignition turned off.

Usually when the electrical system in the car is acting up, it goes backed to two components. The BCM under the driver seat (check the carpet under the seat, and see if it's wet), or the ignition switch.
If I whould have to guess, I whould say ignition switch.
That is a good place to start, as this part is very cheap ( you can get the VW version) and relatively easy to replace.

Didnt Hurricane Harvey just pass through Houston? My bet would be wet electrics.

Since the poster lives in Liverpool, England, I doubt that hurricane Harvey had any impact on his car.

That said, the OP definitely has a water damaged immobilizer. 100%, no doubt.

Ecm Module
 

Thanks for the help guys. The ECM module (under the passenger seat in British cars!!) Was soaked!! As was the carpet. Took it out, dried it. Cleaned all the crystalized deposits ( must have been damp for a while) sorted most of the electrical faults but can't get the roof to close!!

Rear Control Module
 

Further to my recent threads. The rear control module (under passenger seat in UK cars) had got completely soaked. Drying cured some problems but not all. Ended up getting a new rear Control Module which was set up and all faults cleared by Cath Burrows, Porsche in Standish near Wigan (UK). The root cause of the problem was also identified. The roof mechanism had failed on the day I bought the car, the previous owner had the control arms joints replaced, however the had not removed the debris from the old parts which subsequently blocked the drainage holes causing the passenger floor pan to get soaked under the seat. All is well now for £311.

I haven’t had my seat out yet to look but is it possible to raise/space the module up off the floor to protect it from moisture in the event one does get moisture there? I know the best course of action is to keep the drains clear, just wondering.

Once you get the carpet dry you had best find the cause. The issue may not be just the drain holes. When the top rod sockets break they can poke holes in the foam drip pans at the back of the top. Put the top in maintenance mode and visually check the pans on both sides. If the pans look ok then further test by pouring a bottle of water down both pans and make sure the carpet does not get wet behind the seats.