Hi

If you want to have faster start up check which processes and applications start with OS and disable all of them you do not need. The start up time will not take so much time as before. Here some useful tips:

Spyware and adware can significantly slow startup. If your notebook is taking long time to launch, it could be because of spyware or adware. It is recommended to use some anti-spyware/adware program.

Another possible reason your notebook startup is slow: too many installed programs on it, many of which have components that must be launched at startup. Removing unwanted programs will help improve startup performance. To remove a program in Windows XP, select Start, Control Panel, Add or Remove Programs, select the program you want to delete, and click Remove. Unfortunately, programs must be removed one at a time. If in doubt, don't delete.

Windows system tray, located in the bottom right-hand corner of your screen, contains small icons for programs that automatically start with the OS and run in the background and they slow your notebook's startup.
Some system-tray-resident programs let you disable their automatic startup routine. Place your cursor over a program icon you don't think you need to start up automatically and right-click. Select Open, Options, Preferences, or something similar and look for an option that enables the program to automatically start with Windows. Disable the option. The changes should take effect when you restart. If you need those programs you can launch them from the Start menu when they're needed.

Some applications automatically place a shortcut icon in the Startup folder to ensure they launch with Windows. You can put a stop to that. Right-click the Start button and click Explore. Windows Explorer launches with the Start menu selected by default. Click the plus sign next to Programs and click Startup. Shortcut icons will be listed in the right-hand pane. If you're sure you don't need any of the programs to launch automatically, delete or remove the shortcuts from there and then restart your notebook.

Not all programs install an icon in the system tray and run in the background--and yet, they still start up automatically with Windows. You can use Windows' System Configuration Utility to stop programs and tasks from starting up automatically.
Click Start > Run > Type "msconfig" > Choose the Startup tab. Remove the checks from any tasks you want to prevent from automatically launching. Click OK. You'll need to restart for changes to take effect. Click Restart and Windows XP will restart with only the system services and applications running resulting in a very fast logon / startup.
This tweak will disable all non-system startup services and applications so if you have anything you want to run in the background such as anti virus software do not disable that item.

About freezing I can not tell you much. Which voice chat application you use?