Well, let's determine if it's a problem with the server files or installation.
Try connecting to localhost:7777
If that doesn't work (it still restarts etc) then re-download the SA-MP Windows server file (
http://sa-mp.com/download.php)
And then, making sure your other server is closed, launch the default server, without changing any settings in server.cfg.
Then try connecting to localhost:7777
If it still crashes etc, then it's a problem with your SA-MP or San Andreas installation. Uninstall both and then re-install.
If it doesn't crash, then your filterscripts or gamemodes or something in your server is causing it to crash. Check the server log. If that has no clues, then try removing all filterscripts, etc. Trial and error until you find out what is wrong.
Hope this helps.
EDIT:
If your server ping ever goes to 99999, it means that your computer is recieving no response from it. Check that your IP hasn't changed (
http://ipchicken.com). If you're the only one that needs to use the server, just use your local IP or localhost. If other people are using it, I reccomend you get a server host. ServerFFS.com seems to be good for SA-MP servers, but that's only from what I've heard. I myself will be getting a VPS with them in a few weeks.