Phone keeps rebooting

I have a sx66 which used to accept sim card from other network but suddenly it stops so i deleted some programs from my documents and the phone no longer opens it only shows window mobile but would not boot, please what should i do?

Since the icon is located on the screen, have you tried just pushing the send but to get the phone to show up?

Is the button near the reset hole? possibly the button is somehow pressing the reset switch, possibly stuck somehow. Other than that try a hard reset, instructions below.
Soft Reset
Put your stylus in the hole in the lower left corner where it says “Reset” Soft Reset will reboot your device just like when you reboot your PC. No data will be lost, under normal circumstances that is.

Hard Reset
Hold down the Power button (Top Right corner) and at the same time put your Stylus pen in the hole where it says “Reset” (Lower Left corner).
Hard Reset will delete all data you have put on the device, Programs, Settings, Mail, SMS, MMS, etc., so be careful and make a backup before doing this.
After a hard reset, you will have a complete clean new install of Windows Mobile on your device.

Things that are not deleted

• Data on \Storage Card
• Data in \Storage folder