After replacing battery the radio has no power

Hi and thanks for using 2CarPros. Com. Here are directions for removal and replacement of the battery. Pay attention to the beginning cautions.

1999 Volkswagen Cabrio (1V7) L4-2.0L (ABA)
Vehicle  Starting and Charging  Battery  Service and Repair  Removal and Installation
REMOVAL AND INSTALLATION
Battery, removing and installing
CAUTION! Before working on the electrical system:
- Obtain radio anti-theft code.

- Ignition OFF!

- Disconnect battery Ground (GND) strap.

Notes:

- Refer to warnings and safety measures

- Refer to battery handling instructions.

- Some early production vehicles are equipped with batteries that are 190 mm (7.5 in.) Tall. Later production vehicles are equipped with batteries that are 175 mm (6.9 in.) Tall.

- The larger battery is no longer available. If necessary, replace it with the later 175 mm (6.9 in) battery.

Removing
Disconnect battery cable at negative (-) terminal.
Disconnect battery cable at positive (+) terminal.
Remove battery hold-down nut -3- and clamp -2-.
Remove battery.
Installing
Note:
- The latest generation batteries are equipped with a central gas venting system and a fine mesh flame trap - arrow-.
- Function: Gases produced during charging escape through a central opening on side of upper cover A flame trap is integrated into the this position which prevents the flammable gases in the battery from igniting.
- It is extremely important to check that the hose is connected to the central gas venting system and that it has not been disconnected while installing. Only then can the battery vent via the fine mesh flame trap and hose.
- The flame trap is comprised of a small round fiberglass mat with a diameter of 15 mm and a thickness of 2 mm. It works on a similar principle to a valve therefore it allows the gases produced in the battery to vent.
- Position battery and seat lower lip -1- in clamping strip, as shown.
- Retain other lip of battery at battery securinc pedestal -4- using hold-down -2- and M8 x 2 bolt -3-.
- Tighten bolt -3- to 20 Nm (15 ft lb).
- Connect battery positive (+) cable and negal (-) cable or Ground (GND) strap.
Tightening torque (terminal clamping bolt): Nm (44 in lb)
CAUTION! If the battery is not secured properly, normE shock and vibration can damage the batterj plates, which result in premature battery faA
Notes:
- Battery terminal clamps must only be fitted hand without force in order to prevent damage to the battery housing.
- Battery terminals must no longer be greased.
- After reconnecting battery:
- Activate vehicle vehicle equipment such as rc clock and power windows.
- On vehicles equipped with OBD II, activate readiness code.
______________________________________________________

Okay, I have a feeling you didn't get the radio anti-theft code. Here is what I was able to find which I hope helps.

Deactivating anti-theft lock-out

Deactivating the radio is only possible by entering the correct code number for the electronic anti-theft system.

Notes: The code number for anti-theft system is listed along with the radio serial number on the radio card. See Owners Manual.
In order to deactivate radio lock-out, you must switch ignition on, or else the radio will not be able to read the instrument panel number.
This process requires about 5 seconds. During this time, do not attach the scan tool or leave the scan tool attached.
Switch ignition on.
Switch radio on.
Radio displays "SAFE" and then "1000." No button inputs are required.

Using preset station buttons -1- through -4-, enter code number attached to radio card (press preset button -1- to enter first digit in code number, preset button -2- for second digit, and so on).
Once entire code is entered, push (left or right) rocker button toward right and hold until anti-theft coding is activated. A short "beep" denotes activation.
Electronic anti-theft system (Sound System), activating

The electronic anti-theft prevention system is not pre-activated on new radio units.

Anti-theft system is not activated until the proper code number is entered.

Notes: The code number for the anti-theft system is listed along with the radio serial number on the radio card.
If a radio is replaced, the code number from the replacement radio must be used.
Customer must be informed of new code number if it has been changed. See User Manual.
During activation, do not attach scan tool or leave scan tool attached.
WARNING! For security reasons the radio card should never be left in the vehicle.
Switch ignition on.
Switch radio on.
Radio displays "SAFE" and then "1000." No button inputs are required.

Using preset station buttons -1- through -4-, enter code number attached to radio card. Press preset button -1- to enter first digit in code number, preset button -2- for second digit and so on.
Once entire code is entered, push (left or right) rocker button toward right and hold until anti-theft coding is activated. A short "beep" denotes activation.
If code number has been entered into the radio correctly, the diode on front of the radio must blink when the key is removed from the ignition. If the diode blinks, the radio is operational and the anti-theft coding is activated.

Code radio functions accordingly
Check functionality.

I hope this helps you. Let me know if you have other questions.

Take care,
Joe