I have something weird happen. I use Opera. One day, the shortcut of it disappeared off my desktop. I uninstalled Opera Stable, then try to install it. It disappears. Then tried to install Chrome, nothing. What is going on?

Tech Support Guy System Info Utility version 1.0.0.2
OS Version: Microsoft Windows XP Professional, Service Pack 3, 32 bit
Processor: Genuine Intel(R) CPU T2300 @ 1.66GHz, x86 Family 6 Model 14 Stepping 8
Processor Count: 2
RAM: 1014 Mb
Graphics Card: Mobile Intel(R) 945GM Express Chipset Family, 224 Mb
Hard Drives: C: Total - 57231 MB, Free - 29853 MB;
Motherboard: Dell Inc., 0GF470
Antivirus: Norton Internet Security, Updated: Yes, On-Demand Scanner: Enabled