I have a problem with my taskbar notification area. Whenever I start up the computer and get to the desktop, sometimes the icons will appear while at other times it won't.

Any idea why?

Thanks in advance.

It's ether an old Windows bug (Microsoft is not going to fix it) or explorer.exe crashing (you may have malware).

Try a full virus/spyware scan and/or disabling/uninstalling some of the programs that run at system startup.